The 16th International Symposiumon Primatology and Wildlife Science

September 29-30, 2021

The 16th International Symposium on Primatology and Wildlife Science
Schedule at a Glance (updated Sep. 22, 2021）
Wednesday, September 29
JST

13:10

Opening Remarks

G-2
Corlett
14:00
Coffee/Tea BreakCoffee/Tea Break

11:30

O-5
Keuk

12:00

15:00

15:30

G-3
Nakabayashi

G-4
Bernard

10:30

Morning
O-7
Yan
PWS Finishing Talk
O-8
[Withdrawn]
O-9
Hayashi
Coffee/Tea Break

11:00

Present during entire session:
P-15 Onishi; P-16 Boyun Lee;

11:30

13:10

13:30

14:00

14:30

P-22 Pratap Kadam;
P-23 Vilela; P-24 Ruiz;

12:00

15:00

Horie

Coffee/Tea Break

Poster Session I
Core Time: P-1 –P-14
Present during entire session:
P-1 Naito-Liederbach;P-2 Sugimoto; P-3 Hattori;
P-4 Hirata; P-5 Numabe;
P-6 Palacino Gonzalez;
P-7 Sok Hwan Lee; P-8 Arai;
P-9 Piao; P-10 Tanaka;
P-11 Kuriyama; P-12 Lim;
P-13 Yoshimura; P-14 Toyoda

18:00

―1―

G-6
Sarania

P-27 Santa; P-28 Nakamura

Lunch Break

16:30

17:30

O-14
Shibata
PWS Finishing Talk

P-25 Jones; P-26 Chaney;

15:30

13:10

17:00

O-13
Sato
PWS Finishing Talk

Coffee/Tea BreakP-19 Yokoyama;
P-21 Langgeng;

G-5

13:10

O-11
Fasbender

P-20 Yeongju Lee;

Coffee/Tea Break
16:00

O-10
Brooks

P-17 Maeda; P-18 Minami;

12:30
Lunch BreakAfternoon

O-12
Xu

Poster Session II
Core Time: P-15 –P-28

General Discussion

12:30

JST

15:50

O-15
Ryu

Closing Remarks

Working with Communities

O-6
Sukumar

14:30
Forest Animal Ecology

O-4
He

10:00

G-1
Hanya

13:30

11:00

JST

Behavior, Learning, and Ecology of Pan

O-3
Gris
PWS Finishing Talk

Afternoon

Defaunation: loss of seed dispersal services due to extinction of megafauna

O-2
ItaharaIndividual Perspectives

O-1
Zemmoto
10:30

JST

Molecular & Cellular Insights

10:00

Morning

Thursday, September 30

The 16th International Symposium on Primatology and Wildlife Science
P rogram
Note: Pre-recorded talks and live Q&As will take place on Zoom, and poster sessions on LINC Biz.

DAY 1 Wednesday, September 29th, 2021
Time (JST)min. Abstract

10:00-10:10

(10)

Title
Opening Remarks

Speaker

Affiliation

Gen'ichi
Idani

Wildlife Research Center,
Kyoto University

Individual Perspectives

Chair: Susumu Tomiya

10:10 - 10:25

(15)

O-1

Some novel SNPs may affect dogs’
personality in two breeds

Chika
ZemmotoWildlife Research Center,
Kyoto University

10:25 - 10:40

(15)

O-2

“Corvid Tracking Studio” The motion
capture system as a novel tool to study
the gaze of corvids

AkihiroItaharaWildlife Research Center,
Kyoto University

10:40 - 11:00

(20)

O-3

Acute pain in Japanese macaques:development of assessment tools

Vanessa N.
Gris

Primate Research Institute,
Kyoto University

11:00 - 11:15(15)[ Coffee/Tea Break ]Forest Animal Ecology

Chair: Nahoko Tokuyama

11:15 - 11:30

(15)

O-4

Reducing food particle size may not be
important for eating fruits: examining
determinants of fecal particle size inJapanese macaques

11:30 - 11:45

(15)

O-5

Bugs in animal social networks: fromthe field to simulations

KennethKeukPrimate Research Institute,
Kyoto University

11:45 - 12:10

(25)

O-6

Fitness consequences of crop raiding by
elephants

Raman
Sukumar

Centre for Ecological
Sciences, Indian Institute of
Science

12:10 - 13:10(60)[ Lunch Break ]―2―

Tianmeng
He

Primate Research Institute,
Kyoto University

Time (JST) min. Abstract

Title

Speaker

Affiliation[Special Session] Defaunation: loss of seed dispersal service due to extinction of megafauna
Chair: Ikki Matsuda
13:10 - 13:40 (30)G-1

Defaunation in Japan: seed dispersal by
Japanese macaques in Yakushima andtheir extinction in a neighboring island

Goro Hanya

Primate Research Institute,
Kyoto University

13:40 - 14:10 (30)

G-2

Defaunation and the loss of seeddispersal services in tropical Asian
forests

Richard T.
Corlett

Xishuangbanna Tropical
Botanical Garden, Chinese
Academy of Sciences

14:10 - 14:20 (10)[ Coffee/Tea Break ]14:20 - 14:50 (30)G-3Seed dispersal of small seeded-plants,
Ficus on Borneo

14:50 - 15:20 (30)G-4

Do riparian reserves support native
terrestrial small mammal fauna in oil
palm-dominated landscapes?

15:20 - 15:40 (20)
15:40 - 15:55 (15)

Graduate School of Advanced
Miyabi
Science and Engineering,
Nakabayashi
Hiroshima University
Henry
BernardInstitute for Tropical Biology& Conservation, Universiti
Malaysia Sabah

General Discussion[ Coffee/Tea Break ]Sustainable Developmental Goals

Chair: Gen'ichi Idani

The Planet and Humans at a crossroad
and SDGs

15:55 - 16:35 (40)G-5

16:35 - 16:50 (15)

[ Coffee/Tea Break ]16:50 - 18:00 (70)

Poster Session I (on LINC Biz)
Core Time: P-1 ~ P-14

―3―

Masahiko
Horie

Special Assistant to theForeign Minister of Japan

DAY 2 Thursday, September 30th, 2021
Time (JST)min. Abstract

Title

SpeakerMolecular & Cellular Insights

Affiliation
Chair: Takashi Hayakawa

10:00 - 10:20

(20)

O-7

Genetic basis of the speciation in
Sulawesi macaques, Indonesia

10:20 - 10:35

(15)

O-8

[Withdrwan]

10:35 - 10:50

(15)

O-9

A zoo-born white wallaby: disruption of
the melanin synthesis pathway due to an
insertion mutation

10:50 - 11:00(10)[ Coffee/Tea Break ]11:00 - 12:10(70)

Poster Session II (on LINC Biz)
Core Time: P-15 ~ P-28

12:10 - 13:10(60)[ Lunch Break ]Xiaochan
Yan

Primate Research Institute,
Kyoto University

SakuraHayashi

Department of Biological
Science, Kyoto University

Behavior, Learning, and Ecology of Pan

Chair: Yuko Hattori

13:10 - 13:25

(15)

O-10

Oxytocin promotes social grooming inbonobos: evidence for a biobehavioural
feedback loop?

James
BrooksWildlife Research Center,
Kyoto University

13:25 - 13:40

(15)

O-11

Foraging together: food characteristics
associated with large party size inbonobosDavid
Fasbender

Primate Research Institute,
Kyoto University

13:40 - 13:55

(15)

O-12

Chimpanzees can learn to utilize
referential information from video tochoose a tool for future use

Shenwen Xu

Primate Research Institute,
Kyoto University

13:55 - 14:15

(20)

O-13

Understanding of others in chimpanzees(Pan troglodytes): cognitive andaffective underpinnings

Yutaro Sato

Wildlife Research Center,
Kyoto University

How do males associate with other males
in their group? comparative studies ofmale aggression and association patternof the genus Pan

Shohei
Shibata

Primate Research Institute,
Kyoto University

14:15 - 14:35

(20)

O-14

14:35 - 14:50(15)[ Coffee/Tea Break ]Working with Communities
14:50 - 15:30(40)

15:30 - 15:45(15)

15:45 - 15:50(5)Chair: Michael A. Huffman

G-6

Shifting our gaze – towards a just,inclusive approach to research in thefield

BidyutSarania

Centre for Ecological
Sciences, Indian Institute of
Science

O-15

Citibats: citizen science-based bat
monitoring project in Korea

HeungjinRyu

Department of Life
Sciences, Ulsan National
Institute of Science andTechnology

Closing Remarks

Takakazu
YumotoPrimate Research Institute,
Kyoto University―4―

Poster Session I
Coretime: Wednesday, September 29th, 2021, 16:50 - 18:00
Abstract

Title

Speaker

Affiliation

P-1

Diversity of MHC genes of endangered Japanese raptors:
Annegret M.
Wildlife Research Center,a preliminary comparison between golden eagles andNaito-Liederbach Kyoto University
mountain hawk-eagles

P-2

How horses evaluate third-party interactions between
humansTakuto Sugimoto

Wildlife Research Center,
Kyoto University

P-3

Comparison of facial morphology in African wildcats,feral mongrels, and owned domestic cats

Madoka Hattori

Wildlife Research Center,
Kyoto University

P-4

Estimation of food habits of Japanese macaques based on
tooth microwear: detection of variations among regional
populations

Kazuha Hirata

Primate Research Institute,
Kyoto University

P-5

Individual difference in the sensitivity to bitter
compounds in coffee based on TAS2R gene
polymorphism

Rena Numabe

Primate Research Institute,
Kyoto University

P-6

Comparative studies on the social behaviour of magpies
and domestic horses

P-7

Effect of prestigious behavior in social status ofchimpanzees (Pan troglodytes) and bonobos (Panpaniscus)

P-8

Gema
Department of Zoology,
Palacino-Gonzalez University of Extremadura

Sok Hwan Lee

Wildlife Research Center,
Kyoto University

Preliminary analysis on the epigenetic age estimation of
captive Asian elephants (Elephas maximus)

Kana Arai

Wildlife Research Center,
Kyoto University

P-9

Dipping or sucking? Choice of tube-using techniquesin chimpanzees and bonobos before and after video
demonstration

Yige Piao

Wildlife Research Center,
Kyoto University

P-10

Relationship between stress hormone concentration andbehavioral changes in captive Tsushima leopard cats
(Prionailurus bengalensis euptilurus)

Chisato Tanaka

Wildlife Research Center,
Kyoto University

P-11

Reproductive physiology of Iriomote cat (Prionailurus
bengalensis iriomotensis)

Yuko Kuriyama

Wildlife Research Center,
Kyoto University

P-12

Whole-genome resequencing of endangered Malayan
tapir for novel discovery of genome-wide single
nucleotide polymorphism loci

Qi Luan Lim

Wildlife Research Center,
Kyoto University

P-13

Plants for carnivores: Metabarcoding analysis of wildsnow leopards (Panthera uncia) focusing on dietaryplant species

Hiroto Yoshimura

Wildlife Research Center,
Kyoto University

P-14

Ontogenetic differences in mandibular morphology andtheir adaptive significance in Japanese macaques andlong-tailed macaques

Naoto Toyoda

Primate Research Institute,
Kyoto University―5―

Poster Session II
Coretime: Thursday, September 30th, 2021, 11:00 - 12:10
Abstract

Title

Speaker

Affiliation

P-15

Urination behavior of captive chimpanzees: preliminary
study of social factors

Ena Onishi

Wildlife Research Center,
Kyoto University

P-16

Selective infant handling in Yakushima Japanesemacaque (Macaca fuscata yakui)

Boyun Lee

Primate Research Institute,
Kyoto University

P-17

Power-law relationships between a group size and asocial interaction number in animal societies

Tamao Maeda

Wildlife Research Center,
Kyoto University

P-18

Infant Japanese macaques have the most infant-like faces
at around 3 weeks of age during the first 10 weeks

Toshiki Minami

Primate Research Institute,
Kyoto University

P-19

The effects of genito-genital rubbing on affiliative
relationships among female bonobos (Pan paniscus)

Takumasa
Yokoyama

Primate Research Institute,
Kyoto University

P-20

The influence of social bonds of mothers on theoffspring's sociality in feral horse groups

Yeong-ju Lee

Wildlife Research Center,
Kyoto University

P-21

Hot spring bathing behavior and helminth infection in
Japanese macaques at Jigokudani

AbdullahLanggeng

Primate Research Institute,
Kyoto University

P-22

Comparison of foraging patterns between smokers andnon-smokers

Sanjana Pratap
Kadam

Primate Research Institute,
Kyoto University

P-23

Empathy in elephants: integrative approach of behavioral
ecology and cognitive science

Sofia Vilela

Centre for Functional
Ecology, University of
CoimbraP-24

Copy number variation among multicopy Y-chromosome
gene families of rhesus and long-tailed macaques

Cody A. Ruiz

Department of
Anthropology, Kent State
University

P-25

Japanese and rhesus macaques differ in amygdala
cannabinoid 1 receptor-immunoreactive axon density

P-26

Department of
Captive male marmosets (Genus Callithrix) are prone toMorgan E. Chaney Anthropology, Kent Statedental abnormalities, regardless of hybrid status
University

P-27

The effect of ‘brightness contrast’ in luminancediscrimination tasks for killer whales

P-28

Morphological and histoanatomical studies of the larynx
in lemurs―6―

Department ofDanielle N. Jones Anthropology, Kent State
University

Ayumu Santa

Primate Research Institute,
Kyoto University

Kanta Nakamura

Primate Research Institute,
Kyoto University

G-1

Defaunation in Japan: seed dispersal by Japanese macaques in Yakushima
and their extinction in a neighboring island
Goro Hanya1*
1Primate Research Institute, Kyoto University, Inuyama, Japan*hanya.goro.5z@kyoto-u.ac.jp

Unlike many tropical countries, increase, rather than decrease, of large animals is now
regarded to be a conservation issue in Japan. However, many species of Japanese wildlife
suffered from a high hunting pressure and habitat loss until a few decades ago. Local andeven species extinction occurred in many regions in the Japanese archipelago, and some
populations have not recovered since then. Yakushima is an island in southern Japan where thelong-term study of Japanese macaques (Macaca fuscata) has been conducted since the 1970s.
Seed dispersal is one of the topics which is intensively studied for this population and most of
the aspects of pre-dispersal and dispersal phases have been clarified. Japanese macaques havegone extinct in Tanegashima, a neighboring island of Yakushima, until the late 1960s. The twoislands are comparable in size and vegetation, but are quite contrasting in the terrain, humanpopulation and their land use. There is one preliminary study suggesting that the extinction ofJapanese macaques in Tanegashima has resulted in a considerable decrease of seed dispersal
services there, compared with Yakushima where a large number of Japanese macaques are still
surviving. In this talk, I introduce previous studies of seed dispersal of Japanese macaquesin Yakushima, discuss how their extinction can potentially affect forest regeneration andintroduce our new ongoing project trying to reveal the cause and consequences of defaunationin Tanegashima.

―7―

G-2

Defaunation and the Loss of Seed Dispersal Services
in Tropical Asian Forests
Richard T. Corlett1*
1

Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla,
Yunnan 666303, China*

corlett@xtbg.org.cn

The rapid loss of most large vertebrates from botanically intact forests in tropical Asia, andtheir failure to re-colonize regenerating forests on abandoned land, risks an impoverishmentof the future forest flora as many plant species lose their major dispersal agents. The majordispersal agents of seeds in large (>2 cm diameter) fruits—large birds, large bats, elephants,rhinoceroses, primates, and some carnivores—have different degrees of access to the canopy,
different sensory capabilities, different oral and digestive processing, and thus different impacts
on seed fates, so their ecological roles are largely complementary and non-substitutable. To a
subsistence or recreational hunter, however, they are all meat, and the progressive downsizingof the fauna does not necessarily lead to reduced hunting pressure. Seeds in the largest fruits(>4 cm diameter) are dispersed efficiently only by elephants and probably rhinoceroses, butthese megafruits make up < 1% of the regional flora and it is the larger number in the 2–4 cm
range that are of greater concern. This size range includes single- or few-seeded bird fruits,swallowed whole by hornbills, fruit pigeons, and a few other large bird species, similar-sized
fruits taken largely by flying foxes, primate fruits with a peelable protective layer, and otherfruits taken by a wider variety of animals. If we do not reverse defaunation, or compensate byenrichment planting, future forests will be dominated by wind-dispersed and small-fruited (<2cm) taxa, with lower diversity and carbon, and a lower capacity to support large vertebrates ifthey are later reintroduced.

―8―

G-3

Seed dispersal of small seeded-plants, Ficus on Borneo
Miyabi Nakabayashi1*, Abdul Hamid Ahmad2 and Eyen Khoo3
1

Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi Hiroshima,
Hiroshima, Japan

2

Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
3

Forest Research Centre, Sabah Forestry Department, Sandakan, Sabah, Malaysia*

miyabi.nakabayashi@gmail.com

Ficus is famous for its obligate pollination mutualism with fig wasps. To maintainpopulation of pollination wasps, each Ficus individual produces ripe fig fruits asynchronously
and aseasonally, and therefore, each Ficus population exhibits continual fruiting throughout
the year. Because of their year-round fruiting patterns, Ficus are considered keystone foodresources for animals in tropical rainforests, especially when the availability of preferred fruits
is low. There are some animals depend their diet largely on fig fruits. Binturongs and helmeted
hornbills are examples of these animals.
About 80% of binturongs’ diet consists of fig fruits, and over 70% of the Ficus species arehemi-epiphytic figs on Borneo. Available data on helmeted hornbills’ diet on Borneo indicates
they are specialists of fig fruits. In this talk, we introduce how these medium-sized animals
contribute to seed dispersal of figs, especially hemi-epiphytes by comparing the contributionof Müller's gibbons. Our study indicates that binturongs are the most effective seed dispersers
among the three animal species in terms of both quantity and quality at Ficus individuallevel, and helmeted hornbills are also important seed dispersers at Ficus population level.
Unfortunatelly, these two important seed dispersers for hemi-epiphyti figs, especially bearing
large-sized figs, are listed as endangered animals in the IUCN Red List. Considering that fig
fruits serve as keystone food resources for various Bornean animals, loss of these important
disperser would negatively affect other animals and in consequence, ecosystem. More efforts
are urgently needed to implement practical conservation policies for these important seeddispersers.
At last, we will show a tentative result of the comparison of densities of Ficus species inhealthy and empty forests on Borneo. Because of the covid-19 pandemic, we stopped thisstudy now but the result shows that number of Ficus species and fig size in an empty forest
are smaller than those in a healthy forest. This indicates that even small-seeded plants may
also affected by loss of large seed dispersers, and collapse of seed dispersal system might have
happened. We need prompt actions to prevent whole ecosystem collapse.

―9―

G-4

Do riparian reserves support native terrestrial small mammal faunain oil palm-dominated landscapes?
Henry Bernard1* and Nellcy Joseph1
1Institute for Tropical Biology & Conservation, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia*

hbernard@ums.edu.my

Defaunation, generally defined as the loss of wildlife due to human causes such as
deforestation for agricultural purposes, has affected much of Southeast Asia. Retaining
riparian reserves, i.e. narrow strips of natural forests flanking rivers, within disturbed orconverted habitat, is considered a useful way to mitigate wildlife loss in farmland. However,
little is documented for non-volant small mammals in the tropics. We used standardised gridbased sampling to compare small mammal species richness, abundance and community
composition in 14 riparian reserves in old growth forest, logged forest and oil palm
plantations, with that found alongside oil palm rivers with no riparian vegetation. We also
investigated whether the small mammal communities were associated with riparian habitat
covariates to gain an insight into possible optimum characteristics of riparian reserves for thesmall mammal conservation. We found that on average riparian reserves in logged forest andoil palm plantations had significantly more specialist species but fewer generalist species thanareas in oil palm without reserves. All sites had comparable capture rates, but the abundanceof specialist species was higher in logged forest riparian and riparian in oil palm plantationcompared to oil palm without riparian. The opposite trend was observed for generalist species.
Two invasive rats, Rattus rattus and R. exculans, dominated oil palm plantation sites, but werenear absent from riparian reserves, indicating that reserves do not harbor pest rats. Higher
overall small mammal species richness was generally positively associated with closed canopy
forest. While higher small mammal abundance was generally associated with taller canopies
and slightly lower vegetation biomass. The abundance of generalist and invasive species was
negatively associated with canopy closure and understorey vegetation cover. The proportionof forest alongside rivers did not explain the variations in the overall species richness andabundance, but it was significantly positively associated with variations in the richness offorest species. In conclusion, retaining forest-like remnants along rivers in oil palm plantations
is a useful way to enhance small mammal diversity, including forest specialists, and does notappear to promote pest rats in the plantation.

― 10 ―

G-5

The Planet and Humans at a crossroad and SDGs
Ambassador Masahiko Horie1,2*1Special Assistant to the Foreign Minister of Japan

2

Special Advisor to the President of Meiji University*

mashorie@meiji.ac.jp

The Planet and Humans are at a crossroads. The world population is over 7 billion today andwill be reaching 10 billion in the near future. We need to alleviate poverty of over ten billion
people in the world by supporting their economic development.
However, many developing countries’ endeavors for their nation building, in many cases,
lead to further deterioration of environment and huge biodiversity loss.
At this lecture, we will review this conflict between Development and Environment
including problems of global warming and consider what we should do to save this Planet,
Humans and Biodiversity. All the peoples of the world need to uphold the Sustainable
Development Goals (SDGs) which was adopted at United Nations in 2015.

― 11 ―

G-6

Shifting our gaze – towards a just, inclusive approachto research in the field
Bidyut Sarania1*, Krishnapriya Tamma1, Samira Agnihotri1, Subhashini Krishnan1 and Sutirtha Lahiri1
1Centre for Ecological Sciences, Indian Institute of Science, Bengaluru, India*

bidyutsarania@gmail.com

Over the last few years, there has been a growing awareness of the need for decolonizing
ecological research and conservation programmes. Dominant ideas in conservation andecology include those that view nature and humans as separate entities, which value theexploration of “pristine” wild areas and the discovery of “new species”, and the need to createawareness of conservation issues among indigenous and local communities. However, theseideas contain implicit value judgments that many of us will have encountered, expressed withphrases like “my knowledge is better than yours”. Researchers are also usually completely
ignorant of the history of a landscape and its people. Since ecological research is frequently
conducted with help from individuals belonging to ‘native communities’, it is important that
we acknowledge how our ignorance can influence our own field research and practice. It is
often impossible to conduct field research without the guidance of these individuals, whom wecommonly known as field assistants. We strongly feel that there needs to be a paradigm shift –from this framework, and away from extractive practices, towards a culture of practice that isjust, inclusive and collaborative.

― 12 ―

O-1

Some novel SNPs may affect dogs’ personality in two breeds
Chika Zemmoto1*, Minori Arahori1,2, Yuki Matsumoto2 and Miho Inoue-Murayama1
1

Wildlife Research Center, Kyoto University, Kyoto, Japan
2*

Anicom insurance, Inc., Yokohama, Japan

zemmoto.chika.48n@st.kyoto-u.ac.jp

Behavioral characteristic is important for dog keepers. These characteristics are affected byboth genetic and environmental factors. Genetic polymorphisms associated with personality
traits have been reported in several animal species, including dogs. In this study, we aimed
to investigate genetic differences which are related to personality in dogs (Canis lupus
familiaris) using SNPs (Single Nucleotide Polymorphism). We targeted two popular breeds,
Miniature Dachshunds and Toy Poodles. To assess personality, we conducted questionnaires
on 154 Miniature Dachshunds and 222 Toy Poodles enrolled in Anicom insurance, Inc.
The questionnaires consisted of 39 items and were collected along with DNA samples. We
performed exploratory factor analyses on the questionnaire data from each breed and found
6 personality factors (human-directed sociability, aggressiveness, dog-directed sociability,
lively, nervousness, carelessness) in Toy Poodles and 8 personality factors (human-directedsociability, dominance, tolerance, lively, nervousness, aggressiveness, dog-directed sociability,
carelessness) in Miniature Dachshunds. Then, we performed genome-wide association studies(GWAS) on all personality factors in each breed and found novel SNPs associated with thesefactors (p<10 -5). These results provide information about molecular underpinnings of traits
which can threaten the safety of captive individuals and their keepers, such as aggressiveness,dominance and sociability.

― 13 ―

O-2“Corvid Tracking Studio” The motion capture system as a novel tool
to study the gaze of corvids
Akihiro Itahara1* and Fumihiro Kano2,3
1

Wildlife Research Center, Kyoto University, Kyoto, Japan

2

Center for the Advanced Study of Collective Behavior, University of Konstanz, Konstanz, Germany
3

Max-Planck Institute of Animal Behavior, Radolfzell, Germany*

itahara.akihiro.34n@st.kyoto-u.ac.jp

Gaze behavior has been frequently used to examine cognition of nonhuman animals incomparative psychology. However, those studies exclusively tested primates but not bird
species, although many bird species are known for equivalent cognitive abilities. This is due tothe lack of technology and the difficulty in tracking the direction of attention in freely-moving
birds. This study thus developed a novel tool set, which we called “Corvid Tracking Studio(CTS)”, to track head movement of crows using infrared motion-capture system. We also
developed a custom-made application that reconstructs 3-dimensional positions of each bird’seyes and beak tip from a few still images taken by a standard camera. Experiments tested
accuracies of the head-centered coordinate system reconstructed from the eyes and beakpositions of birds and confirmed that estimated errors in its axes were all well within a degree.
We thus show that a motion-tracking system has a good potential to examine the attention of
freely-moving birds with several customizations. In future, we aim to first quantify their useof visual field when attending to a visual target, and then examine how they use their gaze insocio-cognitive experiments by analyzing key gaze behaviors such as eye contact/avoidance,gaze-following, and anticipatory-looking.

― 14 ―

O-3

Acute pain in Japanese macaques: Development of assessment tools
Vanessa N. Gris1*
1

Primate Research Institute, Kyoto University, Inuyama, Japan*gris.vanessa.23n@st.kyoto-u.ac.jp

Changes in facial expression work as non-verbal signals of pain and provide cues forassessing emotional states in mammals. While biomedical research has a continuing demandfor primate models, it is necessary to ensure that laboratory animals are efficiently evaluatedand provided pain relief. However, a validated scale for assessing pain in macaques has yet to
be developed, further aggravating the difficulties inherent to the discrimination of the presence
and intensity of pain in the species. In the past decade, we observed a growing interest in thedevelopment of tools to detect facial expressions of pain. Geometric morphometrics (GMM)
stands among these new methods and has been successfully applied to the analysis of facial
features in humans and domesticated species. This talk will cover several of my projects thathave aimed to identify signals of pain in captive Japanese macaques. In the first study, weapplied GMM in order to analyze facial shape in female Japanese macaques who experienced
surgery. The facial images were collected from video footage of the macaques in two separate
conditions: at least one day before and 1 day after surgery. Forty-four facial landmarks wereselected based on the underlying facial musculature and their corresponding facial action
units and then annotated on each image. Shape information was extracted from the landmark
coordinates with a generalized Procrustes fit and summarized with principal component
analysis. Results showed that pain seems to be associated with tightening of the muzzle, as has
been observed in other species, and apparent raising of the hairline, likely due to piloerection.
We hope to exploit our innate observational bias to focus on the facial region to improve theability to recognize pain in non-human animals. Next, I will report on the use of Artificial
Neural Networks to automate the detection of pain in Japanese macaques based on their facial
expression using the same sample set from the previous study. Finally, it is worth mentioningthat behavioral changes are an important component of pain evaluation. I will briefly reporton an ongoing analysis regarding behaviours associated with stress and pain. The results fromthese experiments may provide us with a better understanding of the behavioral and facialsignals of pain in captive macaques, which will ultimately lead us to efficiently performing
health evaluations and improving their overall care.

― 15 ―

O-4

Reducing food particle size may not be important for eating fruits:
examining determinants of fecal particle size in Japanese macaques
Tianmeng He1*, Wanyi Lee1 and Goro Hanya1
1Primate Research Institute, Kyoto University, Inuyama, Aichi, Japan*

tianmeng.he.43m@st.kyoto-u.ac.jp

Fecal particle size has been widely used in studies on folivores to understand their feeding
and digestion. In folivores, diet composition, dietary toughness, and age-related factors suchas tooth wear are important proximate determinants of fecal particle size. However, primate
fecal particle size studies find different proximate determinants in this taxon, especially infrugivorous and omnivorous species. Thus, it requires further study on interpreting fecal
particle size results in these taxa. This study aims to find out the influence of age-sex class anddiet on fecal particle size in omnivorous Japanese macaques in Yakushima. We documented
the diet composition, dietary toughness, and fecal particle size of Japanese macaques in thelowland area of Yakushima. We also conducted in vitro digestibility assay on food samples
with different particle sizes to estimate the influence of particle size on digestion. Fecal
particle size showed limited variation among different months and no difference among agesex classes. Dietary toughness did not influence fecal particle size. The consumption of fruits
showed marginally significant negative effects on fecal particle size. Particle size had a lessobvious influence on the in vitro digestibility of fruits than it of leaves and seeds. These results
indicate that diet and age-sex-related factors are not important determinants for fecal particle
size in our study subject. Fecal particle size and digestion efficiency may not be negatively
correlated in frugivores and omnivores primate as studies in folivores suggested. Factors
other than what we examined in this study, such as the physical structure of food and chewing
behavior, should not be neglected when interpreting fecal particle size in primate studies.

― 16 ―

O-5

Bugs in animal social networks: from the field to simulations
Kenneth Keuk1*, Julie Duboscq2 and Andrew MacIntosh1
1 Social Systems Evolution, Kyoto University Primate Research Institute, Inuyama, Japan
2 UMR7206 Eco-anthropologie et Ethnobiologie, CNRS –MNHN –Paris Diderot, Paris, France*

kenneth.keuk.57m@st.kyoto-u.ac.jp

Group living has its advantages, but it also comes at various costs. Our times of pandemic
highlight that infectious disease transmission is one of them; think how lockdowns were
decided to limit transmission and protect public health. Animals form groups of varied size,
composition, or structure in the wild. Studying animal social systems can provide insights in
Ecology, Evolution, Cognitive studies, infectious disease-related fields like Epidemiology or
Disease Ecology, and further inform us on the pros and cons of group living.
However, a group is more than the sum of its parts that compose it – the individuals. Even
studying all the pairs of individuals within a group might not tell the full story: a group is acomplex system. This becomes obvious when a social group is modelled as a social network: insuch mathematical object, individuals are represented as the nodes of the network, connected
via their relationships or associations, represented as the network edges. Social networks
inform us on more aspects of the group: how central or peripheral individuals are within it,
how sub-divided or how connected the group is, etc.
Animal Social Network Analysis proved to be a powerful and flexible tool to study social
systems. To showcase this, I demonstrate how animal social networks and individual network
centrality correlates to infection, in the case of the Japanese macaques of Kōshima and theirgastro-intestinal helminths. However, many aspects of Social Network Analysis (SNA) still
deserve more study and the refinement of dedicated tools to help improve analyzing social
systems. One such aspect is network uncertainty, or put differently: how confident can one
be that what has been measured in a network is variable or not around the measure? I present
how Bayesian inference and computer simulations – in the form of the R package SimuNet I
developed – can help study network uncertainty, and why this is important to study animalsocial systems.

― 17 ―

O-6

Fitness consequences of crop raiding by elephants
Raman Sukumar1*, Sanjeeta Sharma Pokharel1, Nishant Srinivasaiah1 and Polani B. Seshagiri2
1

Centre for Ecological Sciences, Indian Institute of Science, Bangalore, Karnataka, India

2

Molecular Reproduction Development and Genetics Department, Indian Institute of Science,
Bangalore, Karnataka, India*

rsuku@iisc.ac.in

Crop raiding by free-ranging elephants is increasingly common in Asia and Africa. The causes ofelephant-human conflicts are related to a complex suite of factors, including proximate factors suchas habitat loss, degradation and fragmentation, adverse climatic events such as droughts, elephantpopulation increase at local scales, increasing greening afforestation and agriculture outside forests,
or ultimate factors related to optimal foraging choices by elephants, behavioural ecology, and culturaltransmission of behaviour.
Elephants take considerable risks in venturing out of their natural habitats to raid agricultural
crops as they may be injured in several ways or even die in the process. We hypothesize therefore
that elephants derive considerable benefits from a crop raiding strategy and that the benefits obtained
potentially outweigh the costs incurred during their crop raiding forays outside their relatively safe
natural habitats. While benefit-cost ratios and their ultimate fitness consequences are difficult tomeasure without long-term studies of populations, we can measure some components (such as
body condition, stress levels, musth in male elephants, and reproductive rates) of fitness benefits inelephants.
The most obvious benefits that elephants derive from crop raiding is superior nutrition from feedingon cultivated plants: several studies have clearly shown that elephants obtain higher quantity of forage
per unit time spent in crop fields and nutrients such as protein and certain minerals. Male elephantstranslate the superior nutrition derived from crops into faster growth in body size and expression ofmusth duration and intensity, potentially enhancing their reproductive success, as seen in studies bothin Africa and in Asia. Bulls are form larger groups with complex hierarchies for crop raiding andlearning. Female elephants in family groups which raid crops in human-dominated landscapes also
maintain better body condition than those which are confined to protected forests. Further, the former
also exhibit lower levels of physiological stress as seen from glucocorticoids measured in faeces,perhaps because of superior nutrition (especially dietary protein) obtained from cultivated plants.
Anecdotal evidence also suggests that elephants ranging predominantly in agricultural landscapes
have higher reproductive rates. Although, the overall benefit-cost ratios in terms of fitness have notbeen quantified as yet, the rapid range expansion of elephant populations in many regions strongly
suggests that the fitness consequences of a crop raiding strategy may be beneficial to elephants under
the present regime of wildlife conservation in many countries. This has implications for the mitigationof elephant-human conflicts and the management of elephant populations.

― 18 ―

O-7

Genetic basis of the speciation in Sulawesi macaques, Indonesia
Xiaochan Yan1*, Kanthi Arum Widayati2, Fahri Bajeber3, Akihiro Itoigawa1,
Laurentia Henrieta Permita Sari Purba2, Bambang Suryobroto2, Yohey Terai4, Hiroo Imai1
1

Primate Research Institute, Kyoto University, Inuyama, Japan2

Department of Biology, Bogor Agricultural University, Bogor, Indonesia
3

Department of Biology, Tadulako University, Palu, Indonesia

4

Department of Evolutionary Studies of Biosystems, The Graduate University for Advanced Studies, Hayama, Japan*

yanxch3@outlook.com

When populations face with different environments, they underwent different directional
selection pressures on the traits. This process often leads to reproductive isolation andecological speciation. Although numerous cases indicate the importance of ecological
speciation in nature, very little is known about the genetics of the process. Sulawesi macaques,
seven endemic species in Sulawesi Island, Indonesia are optimal for studying the mechanismof genes driving speciation. They have rapidly speciated from the common ancestor in a
relative short period. They widely distributed from southern to northern Sulawesi and aremorphologically diversified. Exceptionally, they exhibited distinct dark coat color but withdifference in color pattern between the species. To clarify the genetic basis of speciation in
Sulawesi macaques, we sequenced the exome (all exons) of five species and screen out the highdiverged SNPs and genes. In total, we collected 10 saliva samples of each species in Sulawesi
Island. After determined the exome sequence using human exome library, we computed thesites Fst value of each two neighboring species and filter the top 5% Fst SNPs as high diverged
sites. We found that about 310 genes were highly diverged in all the five species. These genes
might be responsible to the speciation and evolve in directional selection on the traits. Further
we investigated the pigmentation-related genes and confirmed the functional divergence ofthe genes in vitro. We found about 20 pigmentation-related genes were involved in speciation.
We determined the cAMP induced ability of the melanocortin-1 receptor (MC1R), which
regulates the synthesis and density of melanin production. The MC1R exhibited fixed aminoacid sequence in each species and showed specific functional characteristics in each species.
These results demonstrate the genetic basis of the speciation in Sulawesi macaques and thepossibility of coat color divergence mechanism.

― 19 ―

O-9

A zoo-born white wallaby: disruption of the melanin synthesis pathway
due to an insertion mutation
Sakura Hayashi1*
1

Department of Biological Science, Kyoto University, Kyoto City, Japan*hayashi.sakura.26s@st.kyoto-u.ac.jp

A baby girl with white fur and red eyes was born to a mother wallaby of the regularbody color at a zoo in Japan. My analysis of the daughter's genome revealed that her albino
phenotype was caused by an insertion sequence in the tyrosinase gene, which is essential
for melanin synthesis. Furthermore, the insertion sequence was found to be an endogenous
retrovirus which was named walb. Albino animals generally have disadvantages in survival inwild circumstances because of higher sensitivity to UV rays, weakened eyesight, and brightbody color easily found by predator. Therefore, mutant genes leading to the albino phenotype
tend to be eliminated from the gene pool of the host organism. This tendency suggeststhat walb was transposed into the tyrosinase gene recently and still retains transposition
activity. The walb element is a unique example to respond to the question: why virtually all
endogenous retrovirus copies are inactivated in mammals while there are many active copies
in insects and plants.
In addition, I found that walb occurs in the genomes of multiple Australian marsupials,
including wallabies, kangaroos, and koala. This wide distribution suggests that walb wasintroduced into the genome in their common ancestor. Although walb has long been residingin the genome, its transposition activity has been maintained in a limited host linage. In
general, endogenous retrovirus and its host genome are in the relationship of evolutionaryarms race, that is, competing with each other. The walb element may have given some positiveeffect on the wallaby genome and hence may have been maintained there stably.

― 20 ―

O-10

Oxytocin promotes social grooming in bonobos:
evidence for a biobehavioural feedback loop?
James Brooks1,2*, Fumihiro Kano2,3,4, Hanling Yeow1,2, Naruki Morimura1,2 and Shinya Yamamoto1,5
1

Wildlife Research Center, Kyoto University, Japan
2

Kumamoto Sanctuary, Kyoto University, Japan

3

Center for the Advanced Study of Collective Behaviour, University of Konstanz, Germany
4

Max-Planck Institute of Animal Behavior, Germany

5

Kyoto University Institute for Advanced Study, Kyoto University, Japan*

jamesgerardbrooks@gmail.com

Oxytocin has attracted research attention for its role in mammalian social bonding. The
biobehavioural feedback loop hypothesis suggests that the oxytocin system has evolved tosupport the formation and maintenance of social bonds through a positive feedback loop,
where oxytocin promotes social behaviours which then release oxytocin themselves. Oxytocin
is known to be released following social grooming in chimpanzees and female-female sexual
behaviour in bonobos, though it is not known if these social behaviours are involved in sucha loop. We therefore tested the effect of exogenous oxytocin on social behaviour in captive
female bonobos. Bonobos engaged in social grooming more frequently in the oxytocin
condition compared to placebo control, supporting the notion that oxytocin has evolved toform a feedback loop in Pan sociality. They displayed sexual behaviour only once during theobservation period (oxytocin condition) probably due to low social tension, precluding formal
analysis. Additionally, there was a trend for lower rates of abnormal behaviour (regurgitate
and reingest) in the oxytocin condition, possibly related to its known anxiolytic effects. These
results demonstrate that exogenous oxytocin affects naturalistic great ape social behaviour
and provide support for the biobehavioural feedback loop hypothesis of oxytocin in Pan social
evolution.

― 21 ―

O-11

Foraging together: food characteristics associatedwith large party size in bonobos
David Fasbender1*
1

Primate Research Institute, Kyoto University, Aichi, Japan*

david.fasbender.58z@st.kyoto-u.ac.jp

Food availability is considered one of the primary constraints on group size in animalsocieties. Paradoxically, the societies of our hominin ancestors grew larger and more
complex in increasingly food-scarce, seasonal environments. To identify social strategies orenvironmental factors that enable social cohesiveness when food is scarce, we can turn to theclosest living models of our ancestors, bonobos and chimpanzees. This research focuses on thecohesiveness of bonobo parties when foraging in different habitats and seasons. Specifically, itconsiders whether the large party size of foraging bonobos is better explained by overall highfood availability or by characteristics of favorite bonobo foods. Data on bonobo party sizeand composition and ripe fruit availability previously collected at two field sites: ‘Luzaka’ and‘Wamba’ in DR Congo. At both sites food data was collected with monthly transect surveys ofripe fruit. Party size and composition were estimated with camera traps at Luzaka and direct
observation at Wamba. Weak but significant positive relationships were found between party
size and total fruit abundance at both sites. Preliminary analysis suggests abundance of several
favorite foods were also significant predictors of party size. At Luzaka abundance of two
favorite foods were stronger predictors than total food abundance. Ecological characteristics
of favorite foods such as dispersion/clustering, patch size and ephemerality were calculated
as these qualities are associated with social cohesiveness in other primates including humans.
Future research will use a much bigger dataset of bonobo feeding and movement patterns at
Wamba to look at whether bonobos appear to shape their ranging patterns to the distributionof these favorite foods.

― 22 ―

O-12

Chimpanzees can learn to utilize referential information from video
to choose a tool for future use
Shenwen Xu1*, Ikuma Adachi1
1Primate Research Institute, Kyoto University, Japan*

vassxu@gmail.com

Humans make extensive use of referential information to prepare for future encounter withthe corresponding referent. However, we know relatively little about the comparable referential
processing in nonhumans. In a series of four test conditions, we examined if chimpanzees
would use video information to choose a tool for future use. Specifically, we used two rooms
throughout the test. In the first room, we presented a video showing an experimenter preparing
either peanuts or honey in another room where chimpanzees would visit later. Chimpanzees
were then asked to choose one of two tools, a stick or a straw. The stick was functional
only for peanuts and the straw was for honey. We increased social contingent cues stepwise
throughout the conditions, by adding interaction between the experimenter and the subjects
prior to the video presentation. We found most chimpanzees performed better than expectedby chance in the fourth condition where the experimenter had a direct interaction and thenan extra interaction through video with the subjects before preparing the food. The results
suggest that chimpanzees could learn to utilize referential information in video. To rule out thepossibility that chimpanzees simply learned the discriminative cues in the videos, future study
need to confirm their understanding of video with novel situations.

― 23 ―

O-13

Understanding of others in chimpanzees (Pan troglodytes):
cognitive and affective underpinnings
Yutaro Sato1*
1

Wildlife Research Center, Kyoto University, Kyoto, Japan*sato.yutaro.76w@st.kyoto-u.ac.jp

For social animals, cognitive abilities to understand other beings are important to guidetheir behaviors appropriately for social and ecological demands. I examined chimpanzees’
abilities related to understanding of others using eye tracking experiments. First, I examined
chimpanzees’ reactions to others’ injury. I also measured psychophysiological responses (i.e.,
nasal skin temperature) via infrared thermography. Second, I examined their understandingof biomechanical rules underlying others’ movements. I also attempted to use pupillometry
as a proxy for arousal, although the data was difficult to interpret due to some confounding
effects (i.e., visual properties of stimuli). Those studies involved visual information processing
in chimpanzees. Yet, for chimpanzees, auditory information can also be a rich source of
information about other beings. Third, I examined cross-modal processing between visual andauditory information. Specifically, I examined chimpanzees’ associations between conspecificvocal signals (i.e., alarm and food-associated calls) and images of relevant objects (i.e., snakes
and fruits, respectively). Those studies shed light on unexplored aspects of understanding ofothers in chimpanzees and provide methodological implications for future great ape cognition
research.

― 24 ―

O-14

How do males associate with other males in their group?
Comparative studies of male aggression and association pattern of the genus Pan
Shohei Shibata1*1

Primate Research Institute, Kyoto University, Inuyama, Aichi, Japan*

shibata.shouhei.73c@st.kyoto-u.ac.jp

Chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) are known for their large
difference in male aggression. While male chimpanzees frequently show severe aggressive
behaviors in various contexts, aggression among male bonobos is much less intense. Althoughprolonged receptivity in infertile periods in female bonobos is regarded to reduce malecompetition over mating, a previous study suggested that higher-ranking males sire more offspringthan lower-ranking ones. It is still unclear how and to which extent it reduces aggression among
male bonobos. These two species are also different from each other in terms of their grouping
patterns. Although both species have fission-fusion societies as a common basis, the stabilitiesof their temporary parties are largely different. Chimpanzees form parties which vary in size
and members while bonobos form large and stable parties which include most party members.
It is possible that those differences in their aggression and grouping patterns are related. In thistalk, I will share reports focusing on intragroup aggression and the grouping patterns of males
within these two species. In the first study, I conducted focal animal observations of adult malechimpanzees in the M group at Kalinzu Forest Reserve, Republic of Uganda for approximately
6 months in 2018. I found that the number of males in a given party were significantly larger inthe presence of females showing maximum sexual swelling (MS) than in the absence of those
females. I also found that low-ranking males spent more time alone than other males in theabsence of females with MS present in the group. In total, 177 cases of aggressive interactions
were observed. Regardless of the absence/presence of females with MS, the frequency of maleaggressive behaviors per number of males observed in a party increased with the number of males
per respective party. These results suggest that male chimpanzees of different ranks utilize varying
behavioral strategies during party attendance, likely with the aim of reducing the probability of
being attacked by other party males. Second, from 2019, I conducted field observations on 11
male bonobos of the E1 group at Wamba, Luo Scientific Reserve, Democratic Republic of theCongo. The number of bonobo males in a given party were stable and they rarely ranged alone. I
observed 86 cases of aggressive interactions among males and more than half of those interactions
were expressed toward two particular individuals. Those two individuals are siblings and often
showed provocative behaviors toward two higher-ranking individuals from another family line.
These observations suggest that biological kinship plays a large role concerning male aggression
among bonobos.Lastly, I will report on ongoing analyses comparing male association patterns anddiscuss the differences in male association patterns between the two species.

― 25 ―

O-15

Citibats: citizen science-based bat monitoring project in Korea
Heungjin Ryu1*
1

Department of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, South Korea*

ryuheungjin@unist.ac.kr

Citizen science – public engagement in science – is a fast-growing field in science forthe past few decades. Citizen science is also an efficient way to facilitate public educationand to change public attitudes towards the target species. In 2020, there were increasing
concerns on bats conservation due to the COVID-19 outbreak. For example, bats had become
even a persecution target in some countries. To save bats from such devastating conditions
and debunk misinformation about bats, it was urgent for me to establish a public education
program in Korea. With Kids Science Donga and Korea Safety Health Environment
Foundation, I was able to launch a citizen science program ‘Citibats’. The project aimed formonitoring bats in Korea and deepening public understanding of bats. Despite the pandemic
situation, over 50 citizen scientists participated in the project. Children were particularly
motivated and engaged well in the project. In 2020, we were able to conduct 8 waterway
surveys and found 32 bat biodiversity hotspots in Korea. We also identified 14 to 16 bat
species across the country. As there are 21 to 24 bat species in South Korea, we were able tofind about 70% of bat fauna in Korea. The project is being continued this year as a part of the
Earth Loving Explorers project – the biggest citizen science platform in Korea in which over3000 people participated every year. Despite the even worse COVID-19 situation in 2021,
more and more citizen scientists are reporting bats and the data quality is getting better. This
experience made me realized that a citizen science project will facilitate public awareness ofbats and contribute to bat conservation. A citizen science-based program, therefore, will be agood option for researchers who are looking for an efficient way to facilitate public awarenessand conservation of the study species.

― 26 ―

P-1

Diversity of MHC genes of endangered Japanese raptors: a preliminary
comparison between Golden eagles and Mountain hawk-eagles
Annegret M. Naito-Liederbach1*, Yu Sato2, Nobuyoshi Nakajima3, Toru Yamazaki4,
Taku Maeda5and Miho Inoue-Murayama1
1

Wildlife Research Center, Kyoto University, Kyoto, Japan

2

Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh,
Edinburgh, United Kingdom
3

National Institute for Environmental Studies, Tsukuba, Japan
4

Asian Raptor Research and Conservation Network

5

Iwate Prefectural Research Institute for Environmental Sciences and Public Health, Morioka, Japan*

18liedan@gmail.com

Genes of the major histocompatibility complex (MHC) play a crucial role in the immune system ofvertebrates. In theory, the higher the diversity of MHC genes an individual has, the more pathogens it candefend against. Understanding MHC diversity in endangered species is especially important because suchinformation can be used to predict how resilient populations are to pathogens and whether conservation
strategies such as genetic rescue are necessary. Here, we performed a preliminary comparison of thediversities of MHC DRB exon 2 genes of two species of endangered raptors, the Golden eagle (Aquila
chrysaetos japonica) and the Mountain hawk-eagle (Nisaetus nipalensis orientalis). Both species areimportant apex predators of forest/mountain ecosystems in Japan, and are listed as endangered IB by theJapanese Ministry of the Environment – the population sizes of the Golden eagle and Mountain hawk-eagle
are ca. 500 and 2000, respectively. Next generation amplicon sequencing technology (Illumina MiSeq)
and bioinformatic techniques (online server tool AmpliSAT) were used to genotype MHC DRB exon 2
sequences. We found that the number of alleles (Na), mean and maximum number of alleles per individuals
were higher in wild Golden eagles (n = 21, Na = 12, mean = 6.14, max = 8) than in wild Mountain hawkeagles (n = 11, Na = 8, mean = 4.91, max = 6). This difference could be due to the difference in sample size,
but may also be influenced by (1) sampling locations, (2) ecological characteristics, and (3) evolutionary
histories: (1) In this study, Golden eagles were sampled from both northern and western Japan, whereas
Mountain hawk-eagles were mostly sampled from western Japan. (2) It is known that juvenile JapaneseGolden eagles can disperse long distances from their nests (longest record is 300 km) resulting in geneflow throughout the country, while Mountain hawk-eagles do not disperse as far and have been observed
to remain in their natal territories for several years. (3) Golden eagles have a circumglobal, distribution, so
they may have had more opportunities to evolve immunity towards various pathogens compared to theMountain hawk-eagle, which is found only in Asia. Moreover, it is known that Japanese Golden eagles haveexperienced gene flow from two continents (North America and continental Asia) during the last glacial
period, which may have contributed to a diverse pool of alleles in the population. We plan to deepen theanalysis to better understand these differences as well as their functional consequences and hope to apply
the results to conservation.
― 27 ―

P-2

How horses evaluate third-party interactions between humans
Takuto Sugimoto1* and Satoshi Hirata1
1

Wildlife Research Center, Kyoto University, Kyoto, Japan*

takuto1087@gmail.com

Humans evaluate others by observing their interactions with third parties that are notdirectly related to the interests of the observer. However, such third-party evaluation in nonhuman animals has not been well-studied. Here, we asked whether horses socially evaluate
humans based on third-party interactions. We used the same helping paradigm as that inmonkeys (Anderson, Kuroshima, Takimoto, & Fujita, 2013): horses watched one of two actors(attempter) try to open a transparent container to get an object inside, and then the attempter
asked the other actor (helper/non-helper) for help. In the Helper condition, the actor (helper)
responded to the request and helped, whereas in the Non-helper condition the actor (non-helper)
refused to the request by turning away. After the interaction, the two actors offered food to thehorse, and the horse was allowed to choose which actor to take food from. Horses showed no
preference or avoidance in either condition, but older horses tended to avoid the non-helper in
the Non-helper condition. Therefore, in contrast to monkeys and dogs, horses may not havea robust third-party evaluation ability. However, the results also suggest that horses’ social
experience with humans may improve this ability in horses.

― 28 ―

P-3

Comparison of facial morphology in African wildcats, feral mongrels,
and owned domestic cats
Madoka Hattori1,2*, Atsuko Saito3, Shinya Yamamoto1, Miho Nagasawa2 and Takefumi Kikusui2
1

Wildlife Research Center, Kyoto University, Japan2

Department of Animal Science and Biotechnology, Azabu University

3

Department of Psychology, Faculty of Human Sciences, Sophia University*

hattorimadoka@gmail.com

For domestic animals, facial morphology is important in their interactions with humans.
Previous studies have shown that infantile faces cause caretaking behavior in adults. In thisstudy we focused on the facial morphology of cats to clarify changes in facial morphology due
to their relationships with humans. First we compared the facial morphology of four categories
of cats: African wildcats (Felis lybica), feral mongrels owned domestic mongrels and owned
domestic purebred cats (Felis catus). The results showed that the nose length of domesticmongrels and domestic purebred was shorter than that of African wildcats and feral mongrels.
The eye angle of owned domestic purebred cats was significantly looser than that of the othercategories. Two types of changes in facial morphology can be considered: transgenerationalchanges (domestication syndrome) and changes at the level of individual development. We
therefore conducted a questionnaire with owners of domestic mongrels and domestic purebredcats to investigate developmental changes. The results showed that there was no relationshipbetween the number of ownership years, sociability, aggression and facial morphology. These
results suggest that there are changes in cat facial morphology due to human influence andthat these changes may not be "developmental changes" but "genetic changes” (domestication
or de-domestication).

― 29 ―

P-4

Estimation of food habits of Japanese macaques based on tooth microwear:
detection of variations among regional populations
Kazuha Hirata1, Mugino Kubo2 and Masanaru Takai1
1Primate Research Institute, Kyoto University, Inuyama, Japan

2

Graduate School of Frontier Sciences, Tokyo University, Kashiwa, Japan*

hirata.kazuha.75a@st.kyoto-u.ac.jp

Animal teeth play an important role in food comminution through mastication. Contact with foodparticles results in scars on their enamel surfaces. The shape and depth such so called microwear featuresare strongly correlated to the physical properties of the ingested food, so it is possible to estimate thediet from the microwear. Among the microwear analyses, dental microwear texture analysis (DMTA)
is the most popular at present. DMTA utilizes a 3D enamel surface data by a confocal microscope andquantifies using standardized surface roughness parameters. This method allows objective, repeatable 3D
measurements without observer-bias. Since this method is relatively new, it is necessary to verify whether
each parameter is suitable to capture differences in dietary habits. For this purpose, it is useful to compare
microwear texture of different local populations within the same species, where tooth shape and mastication
process are identical. Japanese macaques (Macaca fuscata) are fit for this verification because they varyin diet among regional populations. For example, populations in high latitude region feed a lot of leaves
while populations in low latitude region consume many fruits. In this study, we aimed to detect variationsof food habits among regional populations of Japanese macaques and test how well DMTA is suitable for
estimating the food habits.
We selected about 20 skeletal specimens for each sample of wild Japanese macaques collected in 6
regional populations (Shimokita, Kinkazan, Hakusan, Boso, Koshima, and Yakushima). The 3D coordinate
data of the occlusal tooth surface were obtained using a confocal laser microscope (VK-9700). The data
were analyzed using surface texture analysis software (MountainsMap 9) and two kinds of surface
roughness parameters (ISO25178 and SSFA) were used for comparison between regional populations.
In ISO parameters, we found that these regional populations divided into two groups: the Shimokita–
Hakusan–Boso population (Group A), with relatively low "height" and "volume" parameters, and the
Kinkazan–Yakushima–Koshima populations (Group B), characterized by the opposite tendency of Group A.
In Group A, Shimokita and Boso populations consume leaves at high rate while Group B consumes themat lower rate (Tsuji, 2015). Though dietary data in Hakusan haven’t be compiled, the diet in Hakusan likely
resembles to that of Shimokita because both of them are belong to the heavy snow area in Japan. Proportionof leaves in diet is likely significantly correlated with the microwear texture. Thus, ISO parameters seemto detect variations of food habits among regional populations of Japanese macaques, at least in terms ofdifferences in leaf consumption rate. In terms of SSFA, each parameter was correlated with the rate of fruit
consumption (Calandra et al., 2012). However, the results in this study didn’t clearly show such tendency.
Whether the SSFA detect dietary variation in Japanese macaques should be verified more carefully.

― 30 ―

P-5

Individual difference in the sensitivity to bitter compounds in coffee basedon TAS2R gene polymorphism
Rena Numabe1*, Akihiro Itoigawa1 and Hiroo Imai1
1

Primate Research Institute, Kyoto University, Inuyama*

numabe.rena.44c@st.kyoto-u.ac.jp

The bitter receptor family is consisted by 26 TAS2R genes in human, and each of them canrecognize from a few to hundreds of bitter compounds. There are many Single Nucleotide
Polymorphism (SNP) in TAS2Rs compared to other taste receptors. It can be one of thefactors of inter-individual difference of people’s sensitivity to bitterness or their threshold ofrecognizing it. In this study, we focus on the bitterness of coffee, which is one of the mostconsumed beverages worldwide despite its bitterness. We targeted TAS2R43 and TAS2R46,
which recognize some bitter compounds contained in coffee like caffeine. First, we examinedthe difference of the responsiveness to the bitter compounds in coffee among the haplotypes
by using the proteins expressed in cultured cell. As the results, there were differences in the
responsiveness among their haplotypes in both of TAS2R43 and -46. Second, we performed
the tasting test to know people’s threshold of recognizing the bitter compound included incoffee. Comparison of the threshold data and genotypes of TAS2R43 and -46 would provide
a clue for the inter-individual difference of the bitter taste sense to coffee. In this presentation,
I want to discuss about the effect to the difference of food preference and culture, because theratio of TAS2R43 and -46 haplotypes is different among the world wide populations.

― 31 ―

P-7

Effect of prestigious behavior in social statusof chimpanzees (Pan troglodytes) and bonobos (Pan paniscus)
Sok Hwan Lee1* and Shinya Yamamoto1,2
1

Wildlife Research Center, Kyoto University, Kyoto, Japan

2

Institute for Advanced Study, Kyoto University, Kyoto, Japan*

seokwhan94@gmail.com

In human society, dominance and prestige are both considered viable strategies for attaining
social rank. By sharing novel knowledge with others, humans achieve social rank throughprestige. In contrast, many previous studies have considered only dominance as a means ofachieving social status in nonhuman animals, assuming that forceful and powerful individuals
tend to become high-ranked and thus monopolize vital resources. However, recent studies ona few primate and bird species have shown similar results to human prestige, discovering an
increase in social centrality of performers after sharing their novel skills with group members.
These results raise the question of whether prestige exists in and could affect the social status
of nonhuman animals. To acquire prestige, humans display desirable abilities to followers that
contradict dominant characteristics, indicating that each is decoupled from the other. Yet, moststudies on nonhuman animals have focused only on dominance, and as such there is still alack of investigations on nonhuman animal prestige. Here we propose a plan to study the roleof prestigious behavior in attaining social status in chimpanzees and bonobos in Kumamoto
Sanctuary. We will seed novel knowledge and skill by training a few individuals to operate
a novel apparatus, and then allow other group members to observe and learn the skill fromthem. Then, we will compare the change in the individuals’ dominance ranks and social
centrality in grooming and proximity networks before and after the introduction of the skill.
Based on the results from previous studies, we predict to see an increase in centrality, but nochange in dominance rank. From this study, we hope to reveal how prestige has emerged anddiverged from dominance in humans.
Keywords: Social status, prestige, dominance, centrality in social network, Pan troglodytes,
Pan paniscus― 32 ―

P-8

Preliminary analysis on the epigenetic age estimationof captive Asian elephants (Elephas maximus)
Kana Arai1* and Miho Inoue-Murayama1
1

Wildlife Research Center, Kyoto University, Kyoto, Japan*arai.kana.84p@st.kyoto-u.ac.jp

Asian elephants (Elephas maximus) are classified as endangered by the International Union
for Conservation of Nature (IUCN) due to habitat destruction and poaching in the wild. This
has led to a continuous decline in population size which has caused the number of individuals
to decrease to less than 50,000. Knowing an animal’s age provides essential ecological andconservational information such as population demographics in the wild and appropriate carein captivity. However, current methods are not always accurate and difficult to observe in thewild for many species. This is also applicable for Asian elephants where age estimation isusually done through observing their height, size of tusks and foot dimensions, mostly fromculled individuals and not living. Thus, a better method to estimate their age such as from
faecal DNA is needed.
It is suggested that DNA methylation-derived epigenetic clocks are the most promising
method to estimate age. Epigenetic clocks based on DNA methylation have been shown toaccurately estimate age on humans, mice, primates, cetaceans, dogs, bats, etc.
This study aims to find age-related markers, related to epigenetic changes in Asianelephants that will allow us to estimate age accurately, ultimately to apply for wild individuals.
In this preliminary study, we have extracted DNA from blood samples of known-aged
captive individuals provided by the collaboration of zoos. So far, we extracted DNA from a
total of 35 blood samples of 11 individuals (3 males and 8 females). Age-range was 0.5 – 65
years old. Then we referred to candidate marker genes using information on age-associatedDNA methylation in humans and mouse genes, to design age-associated primers for Asianelephants. To do this, we relied on different programs such as BLAST and have re-designed
the genes, ELOVL2 and RALYL. Through finding the right RT-PCR conditions, amplification
success was seen in both genes suggesting that these genes could be potential age-related
primers for Asian elephants. We are now looking to design more potential age-related primers
and increase the number of samples (blood and faecal samples). DNA methylation profiles willthen be made to see the correlation between the CpG methylation frequency of specific genes
and chronological age using methylation-sensitive high-resolution melting (MS-HRM).
Successfully identified epigenetic clocks could be used for future uses in conservation
efforts where accurate estimates of age are needed to predict demographic trends.
We thank Oji Zoo and Kyoto City Zoo for providing samples.

― 33 ―

P-9

Dipping or sucking? Choice of tube-using techniques in chimpanzees
and bonobos before and after video demonstration
Yige Piao1* and Shinya Yamamoto1,2
1

Wildlife Research Center, Kyoto University, Kyoto, Japan

2

Institute for Advanced Study, Kyoto University, Kyoto, Japan*

spoonasf@gmail.com

The presence of culture in great apes has been confirmed and studied for several decades,
and researches have shown that it is the social learning processes that underpin muchof the primitive culture in these apes. Compared with the sister species, chimpanzees(Pan troglodytes), culture phenomena in bonobos (Pan paniscus) has been relatively lessinvestigated, which is partly due to their scarce tool-use behaviors in feeding contexts. To
achieve a comprehensive understanding of the evolution of human culture, it is essential topromote tool-use researches in bonobos and conduct comparative studies on the two closely
related yet unique Pan species. In the present study, we plan to compare the spontaneous
choice of tube-using techniques in chimpanzees and bonobos before and after the social
learning process, and investigate their visual attention during the learning process. The apes
will be offered a translucent tube, which can be used as either a stick to dip the juice or a straw
to more efficiently suck the juice. The initial method of their tube-using techniques will firstbe recorded. Then, the apes will be provided a video demonstration of the sucking method,
and their visual attention will be analyzed during this learning process. Later, the apes will
be given a second chance to use the tube, and their tube-using techniques will be comparedwith the initial method. We already found some individual variations of tool use techniques.
The impending studies and future results may further demonstrate how the apes allocate theirvisual attention to different video demonstrations and whether they will show some shift or
persistency in the tube-using techniques.
Keywords: Bonobo, Chimpanzee, Eye tracking, Social learning, Tool use― 34 ―

P-10

Relationship between stress hormone concentration and behavioral changes
in captive Tsushima leopard cats (Prionailurus bengalensis euptilurus)
Chisato Tanaka1*, Kodzue Kinoshita1, Akio Iwashita2 and Gen’ichi Idani1
1

Wildlife Research Center, Kyoto University, 2-24 Tanaka-Sekiden-cho,Sakyo, Kyoto, 606-8203, Japan
2

Tsushima Leopard Cat Acclimatization Training Station, 1249 Idzuharamachi Tsutsu, Tsushima,
Nagasaki, 817-0154, Japan*tanaka.chisato.55a@st.kyoto-u.ac.jp

The Tsushima leopard cat is one of only two known wild cat species in Japan, and is anendangered species. Because of its rarity, various efforts are being made to conserve them, and
it is the only mammal in Japan for which a technique of reinforcement has being developed.
Reinforcement is a conservation activity to release captive animals into existing populationsof conspecifics in their natural habitat and then recover their population. However, thesuccess rate reported in other species, especially mammals is totally low, and the technicalimprovement is required. One of the important key is stress. Transfer between facilities andexcessive contact with humans is likely to be stressful for the animals. Previous research has
confirmed that prolong elevation of glucocorticoids (stress hormones) can have a negative
impact on reproductive and immune functions. It has also been reported that high levels of
glucocorticoids affect cognitive function in animals, and if this condition persists for a longtime, it may damage neural tissues involved in learning and memory. However, not all stresshas a negative impact on animals and maintaining a certain degree of stress is also thought
to be important for reinforcement. In addition, it is difficult to identify what is causing stresswhen the concentration of stress hormones is high by simply tracking the fluctuations of stresshormone levels. Therefore, in order to clarify what events are stressors, I have monitored their
behavior change in addition to analyzing the stress hormone concentration.
Stress hormones will be monitored continuously by collecting feces from individuals kept
at the wild acclimatization station of the Tsushima leopard cat and measuring the cortisol
concentration in the feces using the enzyme-immunoassay method. I have also measured stresshormone concentrations of them before and after the transfer to other facility (including zoos)
to investigate how stressful the transfer and environmental changes are for the individuals.
Behavioral observations have been conducted using video data. Since some facilities don’tallow for visual confirmation of the animal’s location, I plan to attach GPS loggers to theindividuals. In addition, by attaching an activity meter, the exercise status of the individuals
will be evaluated. These observations will be continued and compared with changes in stresshormone concentrations in an effort to identify stressors.
Key word: reinforcement, leopard cat, stress hormone, behavioral observation― 35 ―

P-11

Reproductive physiology of Iriomote cat (Prionailurus bengalensis iriomotensis)
Yuko Kuriyama1*, Kozue Kinoshita1, Masako Izawa2 and Gen’ichi Idani1
1

Wildlife Research Center, Kyoto University, Kyoto, Japan

2

Kitakyushu Museum of Natural History & Human History, Fukuoka, Japan*

catman.d7613@gmail.com

The Iriomote cat (Prionailurus bengalensis iriomotensis) has been listed as a CriticallyEndangered on the IUCN Red List, and their population is only about 100 animals. Although
their diet, habitat, and behavioral areas have been revealed, the physiological underpinningsof the reproductive cycle have not been undertaken. In order to increase the population, stablebreeding is necessary, and not only behavior, but also the understanding of their reproductive
physiology is required to promote their breeding.
With the cooperation of Dr. Masako Izawa, who has studied on Iriomote cat for long time,
I have a plan in the physiological study. Firstly, I’ll confirm whether hormones in feces andurine samples of Iriomote cat which have already been collected at the study site over the
past 20 years had been preserved. And then, I will collect new samples at the study site andconduct on-site environmental survey. Using these old and new samples, I’ll compare their
physiological state between environmental differences and time scales. The hormones tobe analyzed are estrogen, the sex hormone, and cortisol, the stress hormone. By analyzingthese, I’ll clarify seasonal physiological conditions about breeding, land suitable for breeding,differences in stress values by location and season.
Key words: Prionailurus bengalensis iriomotensis, endangered species, reproductive
physiology, hormone analysis― 36 ―

P-12

Whole-genome resequencing of endangered Malayan tapir
for novel discovery of genome-wide single nucleotide polymorphism loci
Qi Luan Lim1* and Miho Inoue-Murayama1
1

Wildlife Research Center, Kyoto University, Kyoto, Japan*

lim.luan.77r@st.kyoto-u.ac.jp

The Malayan tapir (Tapirus indicus Desmarest) is the only Asian member of the Tapiridae family
in the order Perissodactyla. This species is native to Peninsular Malaysia, southern Thailand andMyanmar, and the Sumatran Island of Indonesia. It is listed in CITES Appendix I and IUCN Red
List (“endangered”) with a population estimation of not more than 2,500 individuals worldwide.
Population genetic research that are orientated for conservation and population management goals
has been few but accumulating since 2008. With the advancement of sequencing technologies,
reduced costs, and international consortiums such as 1000 Genomes Project and DNA Zoo,
genomic data becomes more affordable as well as accessible for development of new genome-wide
markers (e.g., single nucleotide polymorphism or SNP) and for sophisticated genomic analysis.
Genome-wide SNP markers have been increasingly developed and used for genomic analysis inmany species, including the threatened species, but not in the Malayan tapir. Here, we used genetic
profiles (microsatellite and mitochondrial DNA control region) of a group of Malayan tapirs (n = 31)
in Japanese zoos to select three samples from three genetic clusters (putatively unrelated and eachfrom an origin of Malaysia, Thailand and Sumatra) for paired-end whole-genome resequencing ona Novaseq 6000. The raw reads were treated with the following main pipeline using a combinationof bioinformatics tools: trimming and filtering based on base/read quality and removing of
unpaired reads with fastp, mapping of the filtered paired reads to the public Hi-C genome assemblyof the Malayan tapir (available from the DNA Zoo) with bwa-mem2, and removing of duplicatedreads from the alignments with samtools; before SNP variant calling with freebayes. The called
variants were filtered using bcftools for high-quality biallelic SNPs based on Phred-scaled quality
scores and depth of coverage. Variant sites that were monomorphic or carried missing data were
removed from the SNP dataset. The mean total reads before pipeline was 398.65 million (M) reads(min: 345.19 M, max: 479.48 M) and after mapping 348.98 M (min: 306.57 M, max: 412.12 M).
The mean depth of coverage in the mapped alignments was 20.01 × (min: 17.59 ×, max: 23.64 ×).
Initial variant calling for all three samples discovered a total of 5,686,003 SNPs, of which 226,443
high-quality biallelic SNPs were retained for future analysis. The SNP dataset will be usefulfor preliminary analysis of genetic distance of the three individuals representing three different
regions, for performing a Pairwise Sequential Markovian Coalescent analysis for demographic
history, and for future design of a panel of SNP markers for population genetic/genomic analysis toinform conservation management. We hope to increase the number of samples for whole-genome
resequencing in the future to increase the accuracy of SNP variant calling.

― 37 ―

P-13

Plants for carnivores: Metabarcoding analysis of wild snow leopards(Panthera uncia) focusing on dietary plant species
Hiroto Yoshimura1*, Takashi Hayakawa2,3, Huiyuan Qi1, Dale M Kikuchi4,
Kubanychbek Jumabay-Uulu5, Koustubh Sharma6, Satoshi Hirata1 and Kodzue Kinoshita1
1Wildlife Research Center, Kyoto University, Kyoto, Japan

2

Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Hokkaido, Japan
3

4

Japan Monkey Centre, Inuyama, Aichi, Japan

Department of Mechanical Engineering Science, Tokyo Institute of Technology, Tokyo, Japan
5

Snow Leopard Trust and Nature Conservation Foundation, Mysore, India
6

Snow Leopard Foundation in Kyrgyzstan, Bishkek, Kyrgyzstan*

hrt.yoshimura@gmail.com

Although felids (colloquially called cats) are the obligate carnivores, they sometimes eat plants bothin the wild as well as in captivity. However, little is known about why exclusive carnivores eat plants.
A big cat, snow leopard (Panthera uncia) inhabits high mountains in Central Asia. Interestingly, theirscats contain plant materials more frequently than other Panthera species. Identification of plant species
leads to figure out the interaction between carnivores and plants in alpine ecosystems and understandthe mechanism and adaptation of plant eating in carnivores.
In this study, we aimed to identify plant species in wild snow leopard scats using a DNA
metabarcoding method. 37 scat samples of wild snow leopards in Kyrgyz Republic were investigated.
After whole scat DNA was extracted, five DNA barcode regions (12SV5 for prey vertebrates and ITS2,
rbcL, trnL, ITS1 for dietary plants) were amplified by PCR and then massively sequenced by a Illumina
MiSeq. The collected site, altitude, and date of each scat and sex of each host were tested as potential
factors which affect taxonomic composition of detected plants. The spatial structures were constructedusing Moran's eigenvector maps (MEMs).
As a result, the family Asteraceae and the genus Myricaria species were dominant plant taxa in snow
leopard scats, that is, frequencies of occurrences were 27/37 (73%) and 21/37 (57%), respectively. There
was no clear correlation between prey and plant species in the identical scat (Yule’s Q <0.9). The effectof collected month on plant taxonomic composition was prominent (a permutation ANOVA, P =0.011)
but the constrained proportion was not high (8.1%).
Myricaria spp. were generally not preferred by herbivores. They contain anti-inflammatorycompounds and are known as a traditional medicine in Tibet. Asteraceae species also contains a varietyof plant secondary metabolites and traditionally used for medication by many ethnic people. There werelacks of the correlation between detected vertebrates and plants, indicating that snow leopard voluntary
eat plants because detected plants are not derived from gut contents of prey vertebrates, and perhaps,
the detected plants may have self-medication roles. Analyzing prey animal scats and/or gut contents aswell will clarify whether detected plants from snow leopard scats were derived from prey vertebrates.
Vegetation survey of study sites is also important to know their preference to plant species.
― 38 ―

P-14

Ontogenetic differences in mandibular morphology and their adaptive
significance in Japanese macaques and long-tailed macaques
Naoto Toyoda1*, Tsuyoshi Ito1, Tamaki Sato2 and Takeshi Nishimura1
1

Primate Research Institute, Kyoto University, Inuyama, Aichi, Japan2

Department of Astronomy and Earth Sciences, Tokyo Gakugei University, Koganei, Tokyo, Japan*

toyoda.naoto.33t@st.kyoto-u.ac.jp

The mandibular morphology is determined not only by dietary habits, but also by sexual
selection and allometry (size-shape relationships) in primates. The interspecific facial
shape differences in African papionini (including baboons, geladas, mandrills and drills,
and mangabeys), which are phylogenetically closely related to macaques, are well known
to be formed by truncation or extension of a common ontogenetic allometric trajectory, aphenomenon called ontogenetic scaling. In this study, we compared the ontogenetic patternsof the mandibular morphology in two species of macaques with different body sizes, Japanesemacaques (Macaca fuscata fuscata, hereafter Mff) and long-tailed macaques (Macaca
fascicularis, hereafter Mfa), using geometric morphometrics with landmark coordinates, toshow the ontogenetic phases when the interspecific differences occur and discuss about theiradaptive significances in terms of life history.
The two species of macaques show a major common ontogenetic allometry, whereas theshape-size regression lines are parallel to each other with no significant differences in thedeveloped shape; that is, no ontogenetic scaling occur. This size-shape relationship probably
spared the large-sized Mffs from increased stress at the mandibular symphysis (i.e., mechanicalrestrictions) and simultaneously allowed them to increase their body size adaptively to climaticfluctuation in the Pleistocene (i.e., Bergmann’s effects). Rather, the interspecific differences
in mandibular shape are amplified by an extension of a minor allometry which occurs only
before weaning in Mffs. Such an allometric effect makes the mandible tall and short in Mffs.
These shape differences reflect the mechanical differences in mastication required after molar
eruptions, e.g., the beginning of adult dietary habits: Mffs take tough food items, including
barks in winter. Both species show the same shape development reflecting sexual dimorphism,i.e., canine enlargement and the modifications of its associated features in males, but theinterspecific differences developed in the early phase, i.e., before weaning, are maintained inlater stages.
Thus, while the shape differences in adults are made during a whole growth period in
African papionins, the differences were developed before the time of weaning in thesemacaques. Our comparison of the ontogenetic trajectories successfully provided evidence
strongly supporting for the view that the interspecies differences in mandibular shapewere made for solving the mechanical requirements for dietary habits in a given species ofmacaques which have survived in the fluctuated climate of Pleistocene Asia.

― 39 ―

P-15

Urination behavior of captive chimpanzees: preliminary study of social factors
Ena Onishi1*, Sota Inoue1,3, James Brooks1 and Shinya Yamamoto2
1

Wildlife Research Center, Kyoto University, Kyoto, Japan

2

Kyoto University Institute for Advanced Study, Kyoto, Japan

3

Graduate School of Environmental Science, Nagoya University, Aichi, Japan*

enaonishi@gmail.com

Urination is a basic physiological phenomenon in most animals including humans.However,while urine itself is widely used in physiological studies such as measuring hormones, there
is a lack of research on urination itself in behavioral science. Even in chimpanzees, one of
our evolutionary closest relatives, there has been no detailed study on urination behavior.
The purpose of this study is to gather basic behavioral information of urination such asits frequency and the time of day when urination is likely to occur. We also preliminarily
investigated social factors on urination behavior. We observed four groups of captive
chimpanzees (N=20) for cumulative 421 hours at Kumamoto Sanctuary. We recorded all
urinations with a resolution of 1 second as well as grooming interactions and inter-individual
proximity at 2-minute intervals. The results showed that the average interval of urinations was
3595 sec (SD=3078), but the frequency varied greatly among individuals. We did not find any
clear trend across individuals about the time of day when urination was most frequent. Our
preliminary analysis found no clear effects of social bonding on consecutive urination between
individuals. Further investigation is needed for further understanding of urination behavior.

― 40 ―

P-16

Selective infant handling in Yakushima Japanese macaque(Macaca fuscata yakui)
Boyun Lee1* and Takeshi Furuichi1
1

Primate Research Institute, Kyoto University, Aichi, Japan*

lee.boyun.74x@st.kyoto-u.ac.jp

Female Yakushima japanese macaques (Macaca fuscata yakui) commonly handle otherfemales’ infants since those infants are only a week old. Every female watches for a chance
to handle others’ infants several times a day, but not every infant is their target. It is clearlyobserved that females (attempt to) handle specific infants rather than other infants staying
around them. This selective infant handling would be shaped by individual or social factors: (1)it is a result of seeking for a high success rate of infant handling, (2) it is a form of infant careand (3) it enhances established social bonds of the handlers, (4) it establishes social bonds withhigh ranking females. We studied patterns of infant handling in a bunch of cases that a handler
stays nearby (within 3m) several infants in a large macaque group at the western lowland
forest of Yakushima island. Considering individual information (e.g., age, rank) of handlers
and infants, relatedness between them and behavioral states or events observed in each case,
we try to reveal the meaning of the inequality in infant handling.

― 41 ―

P-17

Power-law relationships between a group size anda social interaction number in animal societies
Tamao Maeda1* and Takeshi Matsumoto2
1

Wildlife Research Center, Kyoto University, Kyoto, Japan

2

Division of Physics and Astronomy, Graduate School of Science, Kyoto University, Kyoto, Japan*

tamao@powarch.com

Power-law (or scaling) relationships between variables X and Y is Y ~ X β. It is wellknown that such a power law could be found in various natural phenomena, for example,
magnitude and frequency of earthquakes, and allometric laws in animal body size. Recently,
one study suggested the scaling relationships between a number of social interactions andgroup size across species (Rocha et al., Sci. Rep. 2021:11:12584). The total edge numbers“E” in three types of social networks, (cooperation, proximity and human friendships),
scaled super-linearly with group size “N”, i.e., E ~ Nβ, where exponent β was 2.08, 1.54 and1.15 respectively. This study argued that this super-linear exponent was derived from thehierarchical structure of social networks. The result is important in that it may reveal common
principles in the group structures across animal species and type of social interactions. Since
the previous study conducted meta-analysis, inter-specific variations in social structures andenvironmental differences were not addressed, although they could largely affect the social andspatial networks. To fully verify those effects, it is necessary to see whether animals flexibly
change the network density according to the changes in a group size, either experimentallyor by long-term observation of a same population. Moreover, the original model assumed
that a sub-group size increases according to a power of three (e.g., 5 (1st level), 15 (2nd), 45(3rd), …). However, in reality, animal sub-group size may have more variations. In this study,
we investigated a natural horse population to verify the power law relationships, and further
optimized the hierarchical model using simulation. Horses form multilevel society, where
several small groups called “units” gather to form a larger group, “herd”. During 2018 – 2019,a herd size ranged from 15 to 123 individuals. With those variations we found that the spatial
proximity network scaled super-linearly with herd size, where the exponent was 1.62, pretty
consistent with the previous study. Our simulations also suggested that E ~ N1.6 relationshipcould be found in various sub-group structures.

― 42 ―

P-18

Infant Japanese macaques have the most infant-like faces
at around 3 weeks of age during the first 10 weeks
Toshiki Minami1* and Takeshi Furuichi1
1

Primate Research Institute, Kyoto University, Inuyama, Aichi, Japan*

minami.toshiki.73m@st.kyoto-u.ac.jp

Human infants have characteristic faces compared with adults. Infants have a wider face, alonger forehead, larger eyes, and a smaller nose and mouth than adults. Some studies show thatthese features get more and more salient for some months after birth. Many researchers may
agree that nonhuman primates also have infantile faces. However, less studies investigate whether
nonhuman primate infants really have characteristic faces, and which facial features indicate
infanthood in each species. Moreover, no study has examined how infantile faces develop during
infancy in nonhuman primates. This study investigated infantile facial features in Japanesemacaque (Macaca fuscata) and the developmental process of infantile faces during the first 10
weeks after birth. The subject was a provisioned group of Japanese macaques in Arashiyama
Monkey Park Iwatayama, Kyoto, Japan. TM took photos of the frontal face of 70 monkeys morethan 5 years old in the group. In addition, TM took facial photos of eight infants which were bornin 2021 every week from their 0 to 10 weeks old. All facial photos were analyzed and the relative
size of each facial features to the head or face were calculated. Additionally, infants’ behaviors wererecorded by ad-libitum sampling every week. Comparisons of each facial features between infants
and adults revealed that a wider face, a longer forehead, larger eyes, and a smaller nose were facial
features characteristic of infants. Unlike humans, the size of the mouth was not an infantile facial
feature in Japanese macaques. This implies that facial features that indicate infanthood may differ
between primate species. Next, these infantile facial features were used to calculate the infantile
face score (IFS) in all facial photos of infants. Based on this score, the development of infantile
faces during infancy was examined, and it was found that, on average, IFS increased from the birth
to 3 weeks of age, and then gradually decreased until 10 weeks of age. Finally, the relationshipbetween IFS and infant’s behaviors was examined. As a result, 3 weeks of age, when the IFS got
the highest, coincided with the time when all infants could walk on their own and some infants
began to explore away from their mother. In humans, infantile faces attract attention and motivate
adults to take care of infants. In addition, human infants are rated as the cutest at 9-11 months ofage, when their mobility begins to develop. Our findings may suggest that, as with humans, infant
Japanese macaques can attract strong attention of other individuals by having most infantile faces
at the time when they have still poor mobility and they are considered to be the most at risk. Moredetailed investigations of the relationship between infantile facial features and behaviors of infants
and caregivers should make fruitful suggestions for mechanisms of caretaking behaviors and forsurviving strategies of infants in nonhuman primates.

― 43 ―

P-19

The effects of genito-genital rubbing on affiliative relationships
among female bonobos (Pan paniscus)
Takumasa Yokoyama1*1Primate Research Institute, Kyoto University, Inuyama, Aichi, Japan*

takumasa.yokoyama.23s@kyoto-u.ac.jp

Primates, including humans, often engage in homosexual behaviors among both male andfemale sexes. Although many previous studies have referred to homosexual behaviors in nonhuman primates to better understand the evolutionary processes of homosexual behaviors,
the explicable functions of homosexual behaviors in humans have yet to be fully elucidated.
Bonobos (Pan paniscus), who are the closest living relatives of humans, frequently engage
in genito-genital rubbing (GG rubbing) among female members, categorized as homosexual
behaviors. GG rubbing appears to be multifunctional (e.g. reconciliation, tension regulation,
expression of social status, social bonding, mate attraction), which helps us receive valuable
insight for understanding the explicable functions of homosexual behaviors in humans.
Considering previous studies in bonobos, the multiple functions of GG rubbing may varyin their magnitude among allopatric bonobo populations. In the current study, I examined
the functions of GG rubbing among female bonobos at Wamba, Luo Scientific Reserve,
Democratic Republic of the Congo, and particularly focused on the hypothesis of social
bonding. I found that the more dyads had close physical proximity, the more they engaged in
GG rubbing, but social grooming did not affect the proportion of GG rubbing. Ages were closein the dyads, which suggested that their dominance ranks also were an important factor on the
proportion of GG rubbing. My results suggest that the dyads whose ages and dominance ranks
were close kept close physical proximity and engaged in GG rubbing frequently to maintaintheir social relationships. Comparing the functions of homosexual behaviors between primates,
including humans, and within the same species in different populations is helpful to shed lighton hypotheses concerning evolutionary explicable functions of homosexual behaviors.

― 44 ―

P-20

The influence of social bonds of mothers on the offspring's sociality
in feral horse groups
Yeong-ju Lee1* and Satoshi Hirata1
1

Wildlife Research Center, Kyoto University, Kyoto, Japan*yjroah@gmail.com

Female horses are known to form and maintain social bonds with other females in apolygynous group ("harem"). The mothers living in this social environment affect theiroffspring's various social traits, as a social role model as well as their first social partner. It has
been reported that foals tend to show affiliative behaviors toward the human who contacted
friendly with the mother horses, and that foals preferentially associate with another foal
whose mother is the most preferred partner of their mothers. The maternal effect on the way
foals build social relationships, however, was little studied in the feral horse group living in
natural social settings. I planned to examine whether and how the mother's social style, suchas the number of social partners and the strength of the social bonds, influences the offspring'ssociality and the dynamics of social relationships. In free-roaming Misaki horse harems withfoals and yearlings, the affiliative/agonistic social behaviors and proximity between horses
have been recorded using a video camera and a drone from summer through early autumn.
As time went by, foals tended to be less close to their mothers and interact with other groupmembers, including their siblings or other foals if they exist, more often than before. Given
that most Misaki horses maintain the harem groups until early winter, more observations
would be needed to examine the development of social relationships of the horse offspring andthe maternal effect on it.

― 45 ―

P-21

Hot spring bathing behavior and helminth infectionin Japanese macaques at Jigokudani
Abdullah Langgeng1* and Andrew J. J. MacIntosh1
1

Social Systems Evolution Section, Kyoto University Primate Research Institute, Inuyama, Japan*abdullahlanggeng@gmail.com

The population of Japanese macaques at Jigokudani Snow Monkey Park, Nagano, display
hot spring bathing behavior (HSBB) during the cold season. HSBB is known to benefit
thermoregulation and reduce stress, but in several human cases it has also been shown toaccommodate transmission of heat-resistant waterborne parasites. To our knowledge, there
are no studies about the impacts of HSBB on parasitism in nonhuman primates. Thus, wetested for a relationship between HSBB and gastrointestinal helminth parasite infection risk
in Japanese macaques. HSBB might increase the risk of infection if hot springs and theirsurroundings are a source of infection. On the other hand, HSBB might decrease the risk ofinfection if it reduces the immunocompromising effects of stress. The study was conducted
over two winter seasons between 2019 and 2021. A total of 148 fecal samples were collected
opportunistically from sixteen adult female Japanese macaques (9 bathers and 7 non- bathers)varying in age, reproductive cycle, and rank. Parasite prevalence (proportion infected) andabundance (egg per gram feces: EPG) were determined using microscopy. We detected three
species of geohelminth (all Phylum Nematoda): Trichuris trichiura, Oesophagostomum
aculeatum, and Strongyloides fuelleborni. Two species, O. aculeatum and S. fuelleborni, were
excluded from analysis due to their low frequency in the host population. Generalized linear
mixed models show that there is a statistical trend of T. trichiura being more prevalent inbathers than non-bathers (p=0.061), but we found no noticeable difference in its abundance. We
also found that the reproductive cycle was associated with T. trichiura, where its prevalence
was lower in cycling than lactating females. While HSBB may have certain benefits, weshould not discount the potential costs, so greater effort is now needed to further test the link
between HSBB and other potential negative health outcomes.
Keywords: Macaca fuscata, parasite transmission, Monkey Parks, Wildlife Tourism, Animal
Behavior― 46 ―

P-22

Comparison of foraging patterns between smokers and non-smokers
Sanjana Pratap Kadam1*
1

Primate Research Institute, Kyoto University, Inuyama, Japan*sanjana.kadam.45c@st.kyoto-u.ac.jp

The dual information processing system is a model that indicates how our brain canroughly be divided into two distinct types of information processing systems: one for heuristic
processes, system 1, and the analytical system, system 2. The heuristic process, immediate
and automatic response system, is associated with affective function, but causes biased
judgment known as cognitive bias. This preliminary study aims to understand the mechanismof cognitive biases and its relation to addiction, in particular those with and without smoking
habits through foraging patterns.
Healthy control subject (past smokers: n = 5, non-smokers: n = 10) and those with smoking
habits (n = 5) were recruited. Recruited participants answered standardized questionnaires
to measure stress, worry and depression, and Foraging Tasks were conducted to measure
exploration tendencies with regards to risk factors. Those with smoking habit showed
increased exploration tendencies, choosing to explore for new and unknown reward and nonsmokers showed the increased exploitation tendencies, exhausting the resources before moving
onto the next one. This could indicate higher risky behavior in smokers.
Our study suggests that smokers may show trends towards more biased behaviors in theabsence of nicotine which could lead to riskier decision making. Understanding individual
differences in smoking habit can help us to elucidate the mechanisms of addiction leading tonovel strategies for smoking cessation.

― 47 ―

P-23

Empathy in elephants: integrative approach of behavioral ecology
and cognitive science
Sofia Vilela1*, Nachiketha Sharma2,3,4, Raman Sukumar2 and Shinya Yamamoto3,5
1

Centre for Functional Ecology, University of Coimbra, Coimbra, Portugal

2

Centre for Ecological Sciences, Indian Institute of Science, Bangalore, India
3

Institute for Advanced Study, Kyoto University, Kyoto, Japan

4

Postdoctoral fellow, Japan Society for the Promotion of Science, Japan5

Wildlife Research Center, Kyoto University, Kyoto, Japan*vpsofia.a@gmail.com

Empathy plays a vital role in the rich social life of humans. The ability to relate to the otherand proper respond to social interactions can be crucial in species with extensive parental care,cooperative activity and complex societies. However, there is no consensus on definitions,mechanisms and evolution of empathy. This is largely due to the lack of comparative studies
with non-human animals. Therefore, it is particularly relevant to investigate empathy in othersocial species and assess to what extent related phenomena can occur. Elephants, having
sophisticated cognitive abilities and complex social organization, are a pertinent study target
to contribute to comparative work in animal empathy. The goal of this project is to investigate
the empathy-related phenomena in Asian elephants. By joining methods and theories of
behavioral ecology and cognitive research, through behavioral observations, data will becollected on Asian elephants on captive settings and in free-ranging conditions in South India.
It is aimed, specifically, to i) investigate the occurrence and the socio-ecological context of
empathy-related phenomena (e.g. consolation) and to ii) examine the differential hemisphericprocessing of emotions (negative vs positive) reflected in distinct lateral tendencies in the
behavior, as a tool to assess emotions in non-human animals. Overall, the present project
intends to contribute to the understanding of the mechanisms and functions associated with
empathy phenomena and, ultimately, to increment the comparative work on animal empathy.

― 48 ―

P-24

Copy number variation among multicopy Y-chromosome gene families ofrhesus and long-tailed macaques
Cody A. Ruiz1* and Anthony J. Tosi1
1

Department of Anthropology, School of Biomedical Sciences, Kent State University, Kent, Ohio, U.S.A.
*

cruiz3@kent.edu

The rhesus macaque (Macaca mulatta) Y-chromosome is prevalent in Indochinese
populations of the parapatric long-tailed macaque (M. fascicularis) due to introgression via
occasional hybridization. Mammalian Y-chromosomes harbor many male-specific singleton
and multicopy gene families directly related to spermatogenesis and aspects of male fertility.
Copy number variation (CNV) analyses have shown that greater copy numbers of a gene are
typically correlated with increased protein expression. We hypothesize that macaques withthe rhesus Y-haplotype, including Indochinese long-tailed populations north of the Khlong
Marui Fault, will have greater copy numbers of spermatogenesis-related Y-genes than thosewith the “native” long-tailed Y-haplotype (i.e. macaques from peninsular Malaysia and the
Sunda Shelf islands). Custom CNV target assays were designed for each of the four multicopy
macaque Y-gene families – HSFY, TSPY, DAZ, CDY – in addition to a custom reference assay
designed from the macaque RnaseP gene. Target and reference assays were subsequently
run on a QuantStudio3 with genomic DNA from rhesus and long-tailed macaques of known
provenience. Raw assay data were then transformed in CopyCaller v2.1. Preliminary results ofeach assay are discussed in the context of rhesus Y-introgression and primate spermatogenesis.

― 49 ―

P-25

Japanese and rhesus macaques differ in amygdala cannabinoid 1 receptorimmunoreactive axon density
Danielle N. Jones1*, Emily L. Munger1, Kristen N. Hirter1, Heather N. Smith1, Chet C. Sherwood2,
Patrick R. Hof 3 and Mary Ann Raghanti1
1

Department of Anthropology, Kent State University, Kent, Ohio, USA

2

Department of Anthropology and Center for the Advanced Study of Human Paleobiology,
The George Washington University, Washington, District of Columbia, USA
3

Nash Family Department of Neuroscience and Friedman Brain Institute,Icahn School of Medicine at Mount Sinai, New York, New York, USA*

djone167@kent.edu

Endogenous and exogenous cannabinoids signal through the cannabinoid 1 receptor(CB1R) to modulate various aspects of social behavior, including aggression and anxiety. In
rodents and primates, CB1R expression in the basolateral amygdala is dense and cannabinoid
signaling in this region has been reported to influence social behavior. Little is known about
how endocannabinoid signaling in the amygdala contributes to primate social diversity.
The behaviorally diverse and species-rich cercopithecoid monkey genus Macaca is an
ideal model for addressing this topic. Japanese (Macaca fuscata) and rhesus macaques (M.
mulatta) display similar social styles in some respects; however, there is evidence to suggest
they differ in their stress response, amygdala structure, and monoaminergic signaling. To
further assess the molecular basis of social style in Japanese and rhesus macaques, weused immunohistochemistry and stereological methods to compare CB1R-immunoreactive(CB1R-ir) axon density in the basolateral amygdala, which is comprised of the lateral, basal,
and accessory basal nuclei. Our study sample included 6 Japanese and 5 rhesus macaques.
Repeated-measures ANOVAs were used to evaluate species differences, with amygdala region
as the within-subjects measure and species as the between-subjects factor. This revealed
significant main effects for species and area (p values < 0.05) with no interaction. Post hoc
tests revealed higher CB1R-ir axon density in the basal and accessory basal nucleus of rhesus
macaques compared to Japanese macaques. Our results suggest that CB1R-mediated signaling
in the lateral nucleus of the amygdala is comparable between the two species, while thedifferences we observed in the basal and accessory basal nuclei may contribute to the nuanced
behavioral differences observed between them.

― 50 ―

P-26

Captive male marmosets (Genus Callithrix) are prone to dental
abnormalities, regardless of hybrid status
Morgan E. Chaney1*, Rebecca R. Ackermann2, Illaira L.C. Bandeira3, Vanner Boere4, Nelson H.A. Curi5,
Fabio T. das Dores6, Lilian S. Fitorra6, Haroldo R. Furuya6, Claudia S. Igayara7, Emma A. Kozitzky8,
Liliane Milanelo6, Silvia B. Moreira9, Camila V. Molina10, Marcello S. Nardi11, Patricia A. Nicola12,
Marcello Passamani, Valeria S. Pedro6, Luiz C.M. Pereira3, Bruno Petri6, Alcides Pissinatti9,
Adriana A. Quirino3, Carlos R. Ruiz-Miranda13, Daniel L. Silva14, Ita O. Silva4, Monique O.M. Silva15,
Juliana L. Summa11, Richard S. Meindl1, Joanna Malukiewicz16,17 and Christina M. Bergey18,19
1

Department of Anthropology, Kent State University, Kent, Ohio, USA
Department of Archaeology & Human Evolution Research Institute, University of Cape Town, Rondebosch, South Africa
3
Centro de Conservação e Manejo de Fauna da Caatinga, Universidade Federal do Vale do São Francisco, Petrolina, Pernambuco, Brazil
4
Institute of Humanities, Arts, and Sciences at the Federal University of Southern Bahia, Itabuna, Bahia, Brazil
5
Ecologia, Epidemiologia e Medicina da Conservação, Departamento de Medicina Veterinária, Unilavras, Lavras, Minas Gerais, Brazil
6
Parque Ecológico do Tietê, São Paulo, São Paulo, Brazil
7
Guarulhos Municipal Zoo, Guarulhos, São Paulo, Brazil
8
Department of Anthropology, New York University, New York, New York, USA
9Centro de Primatologia do Rio de Janeiro, Guapimirim, Rio de Janeiro, Brazil
10
Programa de Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, São Paulo, Brazil
11
Prefeitura Municipal de São Paulo, Secretaria Municipal do Verde e Meio Ambiente - DEPAVE, São Paulo, São Paulo, Brazil
12
Programa de Pós-Graduação, Ciências da Saúde e Biológicas, Universidade Federal do Vale do São Francisco, Petrolina, Pernambuco, Brazil
13
Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
14
Núcleo de Pesquisas em Ciências Biológicas – NUPEB, Federal University of Ouro Preto, Ouro Preto, Minas Gerais, Brazil
15
Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
16
Primate Genetics Laboratory, German Primate Research Center, Leibniz Institute for Primate Research, Goettingen, Germany
17
Faculty of Medicine, University of São Paulo, São Paulo, Brazil
18
Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
19
Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
2*mchaney1@kent.edu

Hybridization is evolutionarily important because of its potential to transmit genetic information
between otherwise distinct evolutionary lineages, and several species of Callithrix are known
to hybridize in the wild and captivity. In previous work, hybrid primates have exhibited dental
abnormalities at significantly higher frequencies than non-hybrids. Therefore, we expected the samefor the hybrid marmosets in this large sample (N = 223). Using captive and wild marmosets sampled
in northeastern and southeastern Brazil, we examined all teeth for breakage, missingness, dislocation,or other abnormalities. We then used logistic regression to build a generalized linear model describing
the main predictors of dental irregularities. Surprisingly, hybrid status was not significantly predictiveof dental problems; rather, the best fitting model contained a significant interaction between sex andcaptivity as the strongest predictor for dental irregularities (p = 0.007). In this model, captive male
marmosets, regardless of hybrid status, were 3.96 times more likely than free-ranging males to havedental abnormalities (95% CI: 1.26-12.46). Conversely, while free-ranging females were 1.9 times as
likely as captive females to exhibit this response, this comparison was non-significant (χ2 = 1.29, p =0.26). The lack of association between dental irregularities and hybrid status is notable in light of thepreexisting work documenting a positive link between these two phenomena in other species.

― 51 ―

P-27

The effect of ‘brightness contrast’ in luminance discrimination tasks
for killer whales
Ayumu Santa1*, Ikuma Adachi1 and Koji Kanda2
1Primate Research Institute, Kyoto University, Inuyama, Aichi, Japan
2

Port of Nagoya Public Aquarium, Nagoya, Aichi, Japan*santa.ayumu.63u@st.kyoto-u.ac.jp

Cognitive abilities are products of evolution and are shaped by both phylogenetic andenvironmental factors. In order to examine how environmental factors have affected on theevolution of cognitive abilities, it is essential to conduct comparative studies on mammals
living in underwater environment, which is far different from terrestrial environment.
Cetaceans (dolphins and whales) have been highly adapted to the underwater environment andhave developed their cognitive abilities according to the characteristics of the environment.
While many researches have been conducted on auditory abilities of cetaceans, it is not wellunderstood how they use their visual abilities.
Through previous researches on cetaceans, it is suggested that contrast of luminancemay play an important role in their visual object recognition of cetaceans with low visualacuity and no color vision. In order to examine how cetaceans perceive contrast, the effect of‘brightness contrast’ was examined through the luminance discrimination tasks for 2 killer
whales in Port of Nagoya Public Aquarium. Research aim was to develop a new researchmethod which enables us to conduct visual tasks for killer whales and to examine whether theeffect of “brightness contrast” was observed or not.
Through luminance discrimination tasks, we succeeded to develop a new experimental
method controlled by a computer and monitors. The results of experiments showed that theeffect of ‘brightness contrast’ was observed in these killer whales. Furthermore, one killer
whale showed the same tendency as humans that the larger the inducer area, the stronger
the effect of brightness contrast was observed. In conclusion, it was suggested that the effectof ‘brightness contrast’ was observed not only in terrestrial mammals but also in marine
mammals. When the effect is occurred, contrast of luminance between object and backgroundis enhanced and helps observers to separate objects visually from background. Therefore, it
was suggested that contrast of luminance could be essential for visual object recognition not
only of terrestrial mammals but also of underwater mammals.

― 52 ―

P-28

Morphological and histoanatomical studies of the larynx in lemurs
Kanta Nakamura1*, Kiminori Sato2, Jacob C. Dunn3, Yuta Shintaku1,4 and Takeshi Nishimura1
1

Primate Research Institute, Kyoto University, Inuyama, Aichi, Japan2

Department of Otolaryngology-Head and Neck Surgery, Kurume University School of Medicine, Kurume, Fukuoka, Japan3

Behavioural Ecology Group, Anglia Ruskin University, Cambridge, United Kingdom
4Japan Monkey Centre, Inuyama, Aichi, Japan*

nakamura.kanta.54h@st.kyoto-u.ac.jp

Madagascar lemurs are well known to have a rich vocal repertoire. The phonation of thelarynx generates the vocal source and determine the major acoustics of the voice, e.g., thelength, loudness, intensity, and chaotic phenomena. In humans, the vibrations of the vocal
folds play a central role in phonation. On the other hand, unique morphological variations in
the laryngeal structures are expected to facilitate vocal repertoires in lemurs.
Diffusible iodine-based contrast-enhanced computed tomography (diceCT) was used to
examine embalmed larynges from 5 genera of lemurs and 3 genera of lorises and galagos forcomparison with catarrhines. The specimens were soaked in 5% solution of I2KI, to visualize
the muscles and soft tissues on the CT scans. The histological structures of an embalmed
larynx of a ring-tailed lemur were also examined.
Lemurs had several derived morphological and histoanatomical features. They had atransverse recess formed in the laryngeal vestibule to make another set of upward folds similar
to the vocal folds. The thyroarytenoid muscle are also inserted into the submucosa of the
upward folds. These features were not observed in lorises and galagos used here that show
solely a vocal fold as in catarrhines. The upward folds have histological features comparable tothe vocal fold. An areolar connective tissue occupied the lamina propria of the mucosa of theventricular folds and stratified squamous epithelium covered them.
The contraction of the vocal muscle takes part in moving the bilateral vocal folds toward
the glottal midline. This action probably moves the upward folds simultaneously in lemurs.
The histoanatomical structures found in the upward folds are distinctive to the vocal folds andthey facilitate vibrations of the vocal folds during phonation. Thus, the present findings are
consistent with the hypothesis that lemurs also use the vibrations of the “second” vocal folds
solely or together with the true vocal folds during phonation. While the acoustic effects ofthe sole or simultaneous vibrations are not yet examined, they are expected to take part in avariety of their vocalizations.

― 53 ―