bluuebunny/crossref_metadata_2025 huggingface dataset:
Comportement vocal des mâles adultes et organisation supraspécifique dans les troupes polyspécifiques de cercopithèques
Authors: Gautier Jean-Pierre , Gautier-Hion Annie
Published: September 2008

Analysis of the vocal behaviour of adult males from different species of Cercopithecus monkeys in a polyspecific troop shows important species differences, which suggest a superspecific organization upon which the extraordinary stability of certain polyspecific associations can depend. In the community studied, the male Cercopithecus pogonias generally controlled the formation and disbanding of polyspecific troops, coordinated their movements and the spacing between troops, while Cercopithecus cephus seemed to be the ‘follower’ species. However, the roles were divided for defence against predators: male C. pogonias gave warning of aerial predators, while male C. cephus generally gave the alarm against terrestrial predators.
Relationship between Social Interactions and Sexual Maturation in Female Saguinus oedipus oedipus
Authors: Tardif Suzette Davis
Published: September 2008

4 female Saguinus oedipus oedipus were paired with strange, unrelated males while 5 remained in their natal family groups. A comparison of the frequency of selected social interactions involving these females when sexually immature versus mature was made. The frequency of sexual and affiliative interactions in male-female pairs was basically unchanged by the female’s maturation. Mother-daughter interactions were also not changed in a consistent fashion by the daughters’ maturation. Females with strange, unrelated males, either alone or as part of their natal group, displayed increases in marking behavior in association with sexual maturation.
Eine Rekonstruktion des Skelettes von A.L. 288-1 (Hadar) und deren Konsequenzen
Authors: Schmid Peter
Published: September 2008

The partial skeleton of Australopithecus from the Hadar Formation, Ethiopia, is reconstructed and compared with other primates. It is demonstrated that the skull of A.L. 288-1 is not as chimplike as it was proposed for Australopithecus afarensis and that the cranial fragments do not differ from Australopithecus africanus. Structural features like the funnelshaped thorax and the pelvis, with its broad iliaca for insertion of musculus latissimus dorsi and the long lever arm of the pubic muscular attachments, invoke a high level of suspensorial behavior. In our opinion, A. africanus is a generalized hominid primate that differs from the specialized African apes, the living pongids beeing too derived to represent a model of a primitive hominoid or hominid ancestor.
Variation and Homology of the Primate Hypoconulid
Authors: Swindler Daris R.
Published: September 2008

The accessory cusp on the posterior surface of M1–2 in Theropithecus gelada is recognized as a hypoconulid, being serially homologous with the hypoconulid on M3. This hypothesis is based on phylogeny, ontogeny, topographic position and occlusal relationships.
Time Budgets and Consortships in Olive Baboons (Papio anubis)
Authors: Bercovitch Fred B.
Published: September 2008

The influence of season, rank, consortships, and gender on the daily time budgets of adult free-ranging olive baboons (Papio anubis) are described. Neither season nor rank have much influence on time budgets. Females in consort reduce the time spent feeding while males in consort do not decrease feeding time, but spend more time feeding while moving. Males are not more vigilant in consort. Gender differences in consort time budgets are small, while gender differences in nonconsort time budgets are pronounced. It is suggested that females may incur a greater energetic cost in consorting than males, but that the lifetime energetic expenditure in mating effort may be equivalent.
Effect of Estradiol-Treated Females on All-Female Groups of Rhesus Monkeys during the Transition between the Nonbreeding and Breeding Seasons
Authors: Ruiz de Elvira M.C. , Herndon J.G. , Collins D.C.
Published: September 2008

Behavior, sex steroid levels and sex skin color were monitored in 2 outdoor-housed all-female groups of rhesus monkeys during the nonbreeding season and into the breeding period. Each group contained gonadally intact and ovariectomized (OVX) females. In one group, 2 OVX females were implanted with estradiol benzoate pellets. Female-to-female sexual behavior, sex skin redness and endocrine indices of ovulation (in intact females) all increased as the breeding season approached. The two groups did not differ with regard to these measures. This lack of difference suggests that the presence of males may be required to mediate socially facilitated out-of-season breeding by females. No strong relationships were detected between steroid levels of intact females and sex skin color or female-to-female sexual behavior in all-female groups.
Qualities and Drawbacks of Radiotransmitted Vocalizations of Monkeys through Laryngophones: New Perspectives in Analysis
Authors: Gautier Jean-Pierre
Published: September 2008

Radiotransmitted (RT) calls of monkeys equipped with laryngeal micro-transmitters are compared with those recorded by an external microphone (AT). Sharp attenuation of background noise and echoes results in better sonograms with RT than AT sounds. Sensitive detection of unvoiced calls or phonatory noises leads to knowledge of the motivational state of the animals and the mechanisms of their vocal production. However, the laryngophone acts as a low pass filter which limits RT spectra below 3 kHz. Constant distance and orientation between sound source and microphone permit us to get absolute (low-pitched call) or relative (high-pitched call) intensity measurements. Their generalization should be possible with the use of a specific weighting filter which would reconstitute the original energy of calls. The system has interesting applications in behavioral and ecological studies.
A Preliminary Field Study of the Moustached Tamarin Monkey (Saguinus mystax) in Northeastern Peru: Questions Concerned with the Evolution of a Communal Breeding System
Authors: Garber P.A. , Moya L. , Malaga C.
Published: September 2008

A preliminary field study was conducted on moustached tamarin monkeys (Saguinus mystax) inhabiting Padre Isla, a small island in the Amazon Basin of northeastern Peru. Data presented indicate that groups are generally composed of 3-8 individuals including a single breeding female, 1-3 reproductively active males, nonreproductive adult females, and offspring. Migration of adults and subadults into and out of established groups is common, and it is unlikely that S. mystax social units represent nuclear or extended families. It is argued that rather than tending towards monogamy, the reproductive biology and mating activities of moustached tamarins are better understood in terms of a communal breeding system. In the case of this and perhaps other callitrichid species, such a system appears to involve female promiscuity and the participation of reproductively active adult male group members in caring for the young. The hypothesis that there is an important relationship between the number of adult male ‘helpers’ and infant survival is discussed.
The Organization of Song in the Agile Gibbon (Hylobates agilis)
Authors: Haimoff Elliott H.
Published: September 2008

The acoustical and organizational features of the singing behaviour of several groups of the monogamous and territorial agile gibbon (Hylobates agilis) were analyzed in detail. The mated adult pairs produce loud and long duet bouts, while the males also produce solo bouts. The duets were found here to be complex, sequentially and interactively organized, while being dominated by the female; whereas the male solos were less complex and there was a distinct progressive elaboration of the phrases as the bout continued. Some functional and evolutionary implications regarding these findings on the songs of this species are discussed.
Parturition in Wild Gorillas: Behaviour of Mothers, Neonates, and Others
Authors: Stewart Kelly J.
Published: September 2008

Two gorilla births observed in the wild are described. There were several similarities between the two parturitions. Both mothers gave birth in the afternoon, in close proximity to other animals, and in both cases, detectable labour was less than 30 min, although 1 female had a more obvious, difficult labour than did the other. Placentophagy was observed in 1 case and suspected in the other. In both instances, the mothers established ventro-ventral contact and groomed their newborns within 45 min of delivery. The female who had the most difficult labour was displayed at aggressively by other adult females and the adult male. This was the only obvious interest shown by the adult male. In both cases, however, other adult females and immatures showed at least a passing interest in the parturient female and/or the neonate, and in 1 case, immatures were particularly interested in the birth debris. These data are similar in many respects to those from a previous gorilla birth observed in the wild, and are related to the captive management of gorillas in zoos. Stressed in particular is the importance of housing females and their neonates with conspecifics.
Geometric Similarity and Heart Weight Scaling: An Application of White’s Criterion of Similarity
Authors: Larson Susan G.
Published: September 2008

Heart weight scaling among members of the primate tribe Papionini is analyzed in relation to the proposal that evolutionary size change may sometimes come about in such a way that geometric similarity is maintained across species. The results indicate that in terms of relative heart weight, the six species examined can be divided into two groups of geometric variants. Although these groupings do not conform to any hypothesized phylogenetic relationships, there is some evidence to support the associations based on shared patterns of ontogenetic development. An account is proposed for the differences between the two groups in terms of derived versus primitive patterns of relative heart weight growth.
Sexual Behavior of Group-Housed Stumptail Macaques (Macaca arctoides): Temporal, Demographic and Sociosexual Relationships
Authors: Estep D.Q. , Bruce K.E.M. , Johnston M.E. , Gordon T.P.
Published: September 2008

A detailed quantitative analysis of sexual behavior in a social group of captive stumptail macaques was conducted. The distribution of copulations both over days and among animals, and the relationships between copulation and various sociosexual patterns were investigated. Copulations occurred erratically over days and were preferentially directed to a small minority of females. Most patterns of sociosexual behavior were at their highest rates during actual copulatory episodes, others occurred independent of ejaculation. It is suggested that the relationships between variables such as social rank, age and parity and sociosexual patterns are quite flexible and probably vary with the species, testing conditions and demographic make-up of the group.
Reproductive Status of Adult Daughters in Family Groups of Common Marmosets (Callithrix jacchus jacchus)
Authors: Evans S. , Hodges J.K.
Published: September 2008

Urine samples were collected from 6 pubertal female common marmosets at approximately 3-day intervals over a period of 3–7 months. All 6 females were the eldest daughters in their family groups. 3 of these females were subsequently removed from their families and sampled in isolation for another 2–3 months. Levels of urinary pregnanediol-3α-glucuronide were measured by radioimmunoassay in order to establish whether these females showed ovarian cyclicity. No cyclical fluctuations in the levels of pregnanediol were observed in the females housed with their families even though the females were of a reproductively mature age. Cyclicity was quickly established (within 18–22 days) when the females were removed from the family. These results are discussed in the light of similar recent investigations on callitrichid reproduction and the behavioural implications are considered.
Morphology, Taxonomic Status and Affinities of the Lion Tamarins, Leontopithecus (Callitrichinae, Cebidae)
Authors: Rosenberger Alfred L. , Coimbra-Filho Adelmar F.
Published: September 2008

A survey of craniodental variability of the three allopatric populations of Leontopithecus reveals that they are morphologically heterogeneous and individually distinctive, with a nonclinal distribution of characters and pattern similarities. These observations correspond with their better known, starkly different coat coloration, and imply important ecological-adaptive differences. Leontopithecus chrysomelas contrasts markedly in its robust physique, relatively massive and anatomically modified incisors, comparatively small cheek teeth and unique cranial shape. Leontopithecus rosalia is smallest and most gracile, with a highly abbreviated premaxilla and reduced anterior dentition. Leontopithecus chrysopygus is quite the largest in most bodily and cranial dimensions yet is more similar to Leontopithecus rosalia in anterior tooth size and proportions, and has a massively built face. Phyletically, Leontopithecus is most closely related to Callithrix (incl. Cebuella) among the callitrichines. Protection of their habitats is urged for there are three times as many species of endangered Lion Tamarins as we had thought.
Life History of Hanuman Langurs (Presbytis entellus)
Authors: Winkler Paul , Loch Hartmut , Vogel Christian
Published: September 2008

Longitudinal data of reproductive parameters from two langur troops (Presbytis entellus) at Jodhpur, Rajasthan, India, are presented. Females can reach menarche at approximately 29 months of age and conceive about 5 months later. Gestation length is about 200 days, average cycling length is 24 days, and mean interbirth interval 15.3 months. Postpartum amenorrhea, which ranges from 80–140 days will be reduced to 23–80 days in cases of stillbirths or early losses of infants, a fact that bears consequences in regard to the discussion of infanticide and reproductive advantage. Troop development showed distinct differences in two neighboring troops, especially in number of surviving female infants until sexual maturity. Both troops taken together, 77.9% of the newborns reached the infant-II stage (6 months), 59.3% survived until their mother’s next infant (average, calculated for the mean birth interval of 15.3 months), and only 35.9% completed the 2nd year of life.
Old Age and Its Behavioral Manifestations: A Study on Two Species of Macaque
Authors: Hauser Marc D. , Tyrrell Gary
Published: September 2008

Observations from two studies on the behavior of stumptail and Japanese macaques revealed that old females were generally less active and involved in fewer social interactions than young adult females. Old females typically avoided or maintained sufficient distance from others to decrease the possibility of interaction, but were neither excluded from social interactions nor out-competed in rank-related situations. The data strongly suggest that the old females selectively withdrew from social interactions and maintained their rank over younger members of the group. Three possible explanations are discussed for the differences in behavior between old and young adult macaque females. (1) Old females with older offspring are less likely to interact with others than old females with younger offspring; (2) old females obtain fewer benefits from social interaction than young adult females, and (3) older females have less energy to disburse for social interaction due to physiological deterioration. The age of the youngest offspring did not account for the decline in social interactions among old females. It was concluded that active withdrawal from social interactions on the part of old females is likely to be the result of both a decrease in the benefits obtained from sociality and an overall physiological deterioration.
Distribution of Pygmy Chimpanzees (Pan paniscus) in the Central Zaire Basin
Authors: Kano Takayoshi
Published: September 2008

Distribution of bonobos (Pan paniscus) in the northern part of the range is estimated to be about 13,500 km2, which includes numerous patches they do not inhabit. Throughout this area, local environmental conditions differ little and bonobos may be said to be stenotopic, as distinguished from eurotopic Pan troglodytes. The bonobos’ discontinuous distribution and overall low density are attributed mainly to human hunting pressure. Further, recent large-scale forest exploitation in this area is considered a great threat to the survival of this rare pongid.
Learning Set Formation in Ring-Tailed Lemurs (Lemur catta)
Authors: Ohta Hirohiko , Ishida Hidemi , Matano Shozo
Published: September 2008

Following the study on nocturnal slow lorises (Nycticebus coucang), the visual discrimination learning set was tested on diurnal ring-tailed lemurs (Lemur catta) under the almost same experimental condition as on slow lorises. Their performance was significantly higher than that of slow lorises (p < 0.005). And this suggested the importance of interspecific comparison among extensive prosimian species and the necessity of comparative neurological studies relating with learning set formations.
Visual Scanning by Tamarins
Authors: Caine Nancy G.
Published: September 2008

Visual scanning of the environment was studied in two captive groups of red-bellied tamarins (Saguinus labiatus). The tamarins scanned throughout the day, but rates of scanning were highest just after arising and just prior to retiring. Scanning increased following the presentation of threatening stimuli, and hidden objects were more likely to be discovered at times when scanning rates were high. These data support the contention that visual scanning is a form of vigilance which has important anti-predator functions for red-bellied tamarins.
Female Reproductive Characteristics in Semifree-Ranging Barbary Macaques (Macaca sylvanus L. 1758)
Authors: Küster Jutta , Paul Andreas
Published: September 2008

Mating activities in a group of 178 Barbary macaques were studied during the breeding season 1982/83. Copulations were observed between the middle of August and the end of March. More than 80% of all copulations were recorded from October to December. Number of estrous periods ranged from 1 to 5, most females (67%) had 2 estrous periods. Most females (87%) conceived during the first estrus. Postconceptional bleedings and 1 postconceptional estrus were observed regularly. Mean interval between the end of conceptional estrus and the end of postconceptional estrus was 28 days. Mean interval between the end of conceptional estrus and the onset of bleeding was 18.2 days. Conception rate was 79%. Conceptions occurred between the end of September and the middle of February. Most females (60%) conceived between the middle of November and the middle of December. Mean gestation length for a viable infant was 164.7 days. Consequences of the strong breeding seasonality are discussed.
Un nouveau genre de Paromomyidae (Primates) de l’Eocène Inférieur d’Europe
Authors: Godinot Marc
Published: September 2008

New material from a small paromomyid found at Palette (Lower Eocene, France) comprises a muzzle and a mandible, each with its anterior incisor. The dental formula is 2123/1013. The anterior upper incisor is trilobate, with less well-formed lobes than in fuscus and lapparenti; this species is new and more primitive. The very large and high-crowned lower incisor shows these related species to differ from Phenacolemur, Ignatius and Elwynella. They are referred to the new genus Arcius, with Arcius rougieri n. sp. as type species. Similarity of the lower incisor with that of Soricids, implantation of the incisors and the development of the terminal cusps on the large upper incisor in the Arcius lineage suggest for this genus an insectivorous specialisation.
Differences in Social Behavior between Ethiopian and Arabian Hamadryas Baboons
Authors: Kummer Hans , Banaja A.A. , Abo-Khatwa A.N. , Ghandour A.M.
Published: September 2008

Papio hamadryas were surveyed at 4 distant locations between Taif and Abha in Saudi Arabia. External appearance and motor patterns are very similar to the samples studied in Ethiopia. The adult sex ratio was higher in the Arabian samples and may explain observations and data indicating a higher degree of female choice in the Arabian samples. The Arabian baboons were less strict in selecting inaccessible cliffs for the night and, at the only site without indirect provisioning by humans, travelled mostly as separate one-male units. These differences suggest effects of the lower predator pressure in Arabia.
Adult Male Sociality and Reproductive Tactics among Orangutans at Tanjung Puting
Authors: Galdikas Biruté M.F.
Published: September 2008

During a 4-year period at Tanjung Puting Reserve, Central Indonesian Borneo, adult male orangutans were observed for 2,670 observation hours as focal individuals. Adult male sociality centered around females. Almost the entirety (90%) of adult male participation in social groupings consisted of consortships. If time spent with recent consort partners is included, then adult males spent 95 % of the time that they were in social groups with consorts. Otherwise adult males were quite asocial. Adult males were totally intolerant of each other. Only two brief encounters between lone adult males occurred although avoidance of contact was seen 14 times. Another two encounters between adult males in the presence of females involved much aggression and included a lengthy combat in which the male consort defeated another adult male. Thirty copulations involving adult males were seen; only one copulation was a resisted mating. The other copulations all occurred in consortship. Ten consortships were seen; three involving adult females. While subadult male reproductive tactics predominantly consist of sneak/’rape’, adult male sexual strategy consists primarily of consort/combat tactics. Thus, adult males are interested in attracting and guarding receptive, fertile females. For this reason, wild adult males are relatively selective in choice of consort partner and may reject small proceptive adolescent females.
Anterior Dentition of Notharctus and the Adapid-Anthropoid Hypothesis
Authors: Rosenberger Alfred L. , Strasser Elizabeth , Delson Eric
Published: September 2008

We describe the morphology of the first complete incisor-canine complex for Notharctus tenebrosus. Gregory’s classic description, based on heavily reconstructed and fragmentary material, needs to be amended to include the following points: I1 occludes simultaneously with I1–2; I2 is essentially nonocclusal and staggered behind I1; RI1 and LI1 do not contact interstitially but are separated by a small median diastema; I1 bears a prominent mesial prong. These five features are distinctly lemuriform in appearance: in general Notharctus is phenetically most similar to the pattern found in some lemurids and indriids. We consider an abstraction of the common plesiadapiform-omomyid anterior dental configuration as the primitive primate character state and argue that the adapid (sensu lato) morphology is derived. We further suggest that this predominantly Eocene group is the sister taxon of modern lemuriforms. The incisor-canine morphology of Adapts and Leptadapis is autopomorphic and less suggestive of the primitive pretoothcomb strepsirhine dentition than the notharctine pattern appears to be. While the morphologically simple lower incisors of notharctines are truly similar to those of anthropoids, the preponderance of anatomical differences within the incisor-canine complex leads us to conclude that these similarities were convergently evolved in adapids and the higher primates. The least refuted hypothesis of anthropoid origins, and the one which appears to make most phenetic as well as cladistic sense, acknowledges the monophyly of the Haplorhini and the likelihood that anthropoids are descendants of an early tarsiiform stock.
Observations on the Interaction between Adult Infant-Carrying Animals and Group Members without Rearing Experience in the Common Marmoset, Callithrix jacchus
Authors: Engel Claudia
Published: September 2008

The behavior of animals without rearing experience towards adult, infant-carrying animals and towards the infants being carried, and the reactions of the adult, infant-carrying animals in the latter case are described here on the basis of the observations made of three family groups of Callithrix jacchus (marmosets). In about 50% of the episodes observed, the animals without rearing experience do not establish physical contact with either the infant carrier or the infant; up to 10% of the time they interact with other group members who are also in the vicinity of the infant-carrying animal, physical contact with either the infant carrier (a parent infant carrier is preferred) or the infant accounts for half of the remaining episodes, respectively. More than half of the time when an animal without rearing experience seeks contact with them, the infant carriers do not display any interactive behavior. The percentage of dissociative behavior is highest when the animals without rearing experience seek physical contact with the infants. The percentage of associative behavior is highest when these animals seek physical contact with the infant carrier. Infant carriers break off contact more frequently than do the inexperienced animals. The reaction spectra of the parents differ from those of the adult sons and daughters. The results point to a relatively high level of tolerance on the whole, on the part of the infant-carrying animals; they only react agonistically in situations that are potentially hazardous for the infant. Previous observations have to be qualified by means of the quantified data.
Cytogenetic Study of a New Subspecies of Hapalemur griseus
Authors: Warter S. , Randrianasolo G. , Dutrillaux B. , Rumpler Y.
Published: September 2008

A new subspecies of Hapalemur griseus has been discovered in the area of Fort-Dauphin, Madagascar. It is proposed to name it H.g. meridionalis. The animals resemble the other gentle lemurs except that they are slightly bigger. Chromosomal study shows that their karyotype differs from those of the other gentle lemurs, and a comparison permits the construction of a phylogenetic tree for the genus Hapalemur. Thus, this new subspecies is characterized by its morphology, its karyology and its geographical distribution.
Baboon Diet: A Five-Year Study of Stability and Variability in the Plant Feeding and Habitat of the Yellow Baboons (Papio cynocephalus) of Mikumi National Park, Tanzania
Authors: Norton Guy W. , Rhine Ramon J. , Wynn Gail W. , Wynn Roger D.
Published: September 2008

The habitat and plant feeding of 64 well-habituated, individually identified adult male and female yellow baboons was studied for 5 years at Mikumi National Park, Tanzania. Variation across the years showed that a study of only one or two years would have been incomplete and misleading. The list of baboon food species obtained from Mikumi is considerably larger and more diverse than any previously reported. One to six plant parts were eaten from each of more than 180 species. The 25 most common tree genera all contained species used for food. Of the 50 most common grass, shrub and herb genera, 93% included plant foods. Using months in which a species was eaten during at least one year of the study, 21 staple species were eaten during a mean of 8.86 months and 7 were eaten in all 12 months. Although many foods were from commonly available plant species, 15 such species were only rarely eaten. The number of parts of a species eaten per month and an estimate of the amounts eaten per month both varied with temperature and rainfall, being lowest near the end of the cool, dry season. There were substantial differences from year to year in the timing and amount of food production of many species; nevertheless, the same broad feeding pattern was repeated in each of the 5 years of the study. Despite yearly variation in food availability, 14 or more staples and other common foods were eaten in any given month. If crops of many of these foods were to fail, a large number of less commonly eaten species could be substituted. Baboons are eclectic feeders that appear to be optimizing their diet by selective feeding from among a wide array of available foods in an ever-changing floristic environment.
Termination of Retinofugal Fibers and Lamination Pattern in the Lateral Geniculate Nucleus of the Gibbon
Authors: Tigges Johannes , Tigges Margarete
Published: September 2008

The lateral geniculate nucleus (LGN) of the gibbon (Hylobates sp.) consists of four principal layers, i.e., layers 1 and 2 containing large somata and layers 3 and 4 comprising medium-sized neurons. In addition, there are intercalated layers S, imm and imp, each consisting of small cells. Tracing of retinofugal fibers with the autoradiographic method revealed that the retina projects to the ipsilateral layers 2, 3 and imp and to the contralateral layers 1 4, S and imm. No ‘hidden’ layers have been found. This type of lamination pattern sets the LGN of the gibbon apart from that of all Old World monkeys, chimpanzee and man. Retinal projections to other subcortical regions are also described.
Successful Artificial Insemination in Lemur fulvus mayottensis
Authors: Brun B. , Cranz C. , Ishak B. , Clavert A. , Hugues F. , Leclerc M. , Rumpler Y.
Published: September 2008

A method is reported for collection of sperm by electrostimulation or prostatic massage in order to carry out artificial in utero insemination in Lemur fulvus mayottensis. Using fresh sperm, one success out of 7 attempts was obtained, although it was achieved with a vesiculectomized male.
Field Observation of Snake-Mobbing in a Group of Saddle-Back Tamarins, Saguinus fuscicollis nigrifrons
Authors: Bartecki Ursula , Heymann Eckhard W.
Published: September 2008

At the Rio Blanco in Northeastern Peru a group of 6 saddle-back tamarins was observed to mob two Corallus enydris snakes which were hanging from a liana. These and other observations of snake-mobbing demonstrate that callitricids exhibit a special behaviour against potential predators, which is very similar to the mobbing displays of birds and other mammals. It is suggested that the adaptive significance of snake-mobbing in tamarins lies in the cultural transmission of information about potential predators.
Social Structure in a Wild Group of Macaca thibetana at Mount Emei, China
Authors: Deng Ziyun , Zhao Qikun
Published: September 2008

Data on social interactions were collected mainly in the non-mating season, for one wild but partly provisioned group of Macaca thibetana whose members were individually recognized. Analysis of spontaneous and induced agonistic interactions revealed that a linear dominance hierarchy existed among individuals as in most macaque species studied to date. Social rank among the 1- to 2-year-old juveniles was basically determined by the positions of their mothers. Spontaneous agonistic interactions among adult males were much less common than those among adult females. Data on association showed that mother-infant and mother-yearling bonds were the strongest. Adult females and 2- to 4-year-old juveniles were commonly found in association. Adult males and 3- to 7-year-old males infrequently associated with each other apart from the alpha male and the beta male. Play mainly occurred among immatures, and members of the same age and the same rank preferred to play together.
Social Relations in Groups of the Black-Capped Capuchin Cebus apella in Captivity
Authors: Welker Christian , Becker Petra , Höhmann Hella , Schäfer-Witt Cornelia
Published: September 2008

Infants of the black-capped capuchin are carried on the back of the mother in a transverse position for the 1 st month of life and subsequently in a longitudinal position. In addition to the mother, brothers and sisters frequently interact with the infants. The first 6 months of life are hence the ‘kin phase’ in the life of the infants.
Positional Behavior and Limb Bone Adaptations in Red Howling Monkeys (Alouatta seniculus)
Authors: Schön Ybarra Miguel A. , Schön Miguel A.
Published: September 2008

Morphological adaptations to climbing (a scansorial mode of quadrupedal, arboreal locomotion practised on twigs and small branches) are identified by relating anatomical details of limb bones to a sample of 6,136 instantaneous observational recordings on the positional behavior and support uses of 20 different free-ranging, adult red howlers. Our findings are used to infer the original habitat in which proto-red howlers may have acquired such adaptations and to hypothesize that climbing and its related anatomy are a primitive condition for anthropoids.
Flexibility in Diets of Three Species of Costa Rican Primates
Authors: Chapman Colin
Published: September 2008

Variability in diet and dietary overlap were documented for the three species of primates in Santa Rosa National Park, Costa Rica (Ateles geoffroyi, Alouatta palliata, Cebus capucinus). All three species exhibited great flexibility in their diets, such that in 1 month a monkey species could be considered as having one type of diet (e.g. frugivorous), while in a subsequent month it would be classified as having a different type of diet (e.g. folivorous or insectivorous). It is suggested that such variability in diet and dietary overlap make it unlikely that competition just between these primate species was a strong selective pressure determining their diets.
Sexual Dimorphism in the Cranium of Infant and Juvenile Orangutans
Authors: Winkler Linda A.
Published: September 2008

The present study examines sexual dimorphism in the cranium of the immature orangutan. A series of 37 craniometric dimensions were measured on 56 immature crania. The total sample was divided into two subsamples: infants and juveniles. Univariate statistics and an analysis of variance were prepared for each subsample. Results indicate that the males and females in both subsamples are significantly different (p ≤ 0.05) for two measures of skull length. Eight additional dimensions from the infant category also appear to differ significantly (p ≤ 0.05) between the sexes.
Hand Abnormalities in Pygmy Chimpanzees (Pan paniscus)
Authors: Zihlman Adrienne L.
Published: September 2008

Hand deformities in 2 wild-born pygmy chimpanzees were investigated through dissection, linear measurements, bone mineral analysis and X-rays. Weight of tissue (skin, muscle, bone) was determined for each body segment (hand, forearm, upper arm), permitting comparison between the abnormal and normal upper limbs. In one individual, the right and left forearms and hands differed in tissue weights and bone mineral content. In the other, the hands differed in tissue composition, but not the forearms.
Rapport préliminaire sur les singes de la région montagneuse de Huanchaca, Bolivie
Authors: Braza Francisco , García Juan Enrique
Published: September 2008

Primate censuses were conducted along transects (450 and 1100 m) in forests at Huanchaca (Bolivia) during the months of August and September 1986. As yet, relatively little information is available for primate populations in Bolivia and this is the first report on eastern populations. Average group sizes determined were: 12.8 ± 5.1 for the spider monkey Ateles paniscus (n = 11), 16.2 ± 7.6 for the capuchin monkey Cebus apella (n = 9) and 9.5 for the marmoset Callithrix argentata melanura (n = 2). Population densities determined were: 84.5 individuals/km2 for Ateles paniscus and 38.9 individuals/km2 for Cebus apella. The presence of Alouatta caraya and Aotus azarae was also indicated by their vocalizations, but no counts were possible. This forest area is as yet relatively intact, as indicated by the unusually high densities of spider monkeys in comparison with other neotropical forest areas, but impending schemes to exploit these forests and to construct roads in the region represent a threat to the primate populations and their environment.
Foot Morphology and Locomotor Adaptation in Eocene Primates
Authors: Gebo Daniel L.
Published: September 2008

Locomotor diversity of Eocene primates of North America and Europe was well developed, with species of both Adapidae and Omomyidae showing a wide spectrum of movements. Besides documenting the locomotor diversity in the Eocene, this paper shows that adapid foot morphology shares derived features with extant strepsirhines. Thus, the Omomyidae best resemble the ancestral euprimate in terms of foot morphology and locomotion. The generalized locomotor repertoire of the modern cheirogaleids represents the best model for the movement pattern of the ancestral euprimate.
Changes in Female Reproductive Condition following Male Take-Overs in a Colony of Hamadryas and Hybrid Baboons
Authors: Colmenares Fernando , Gomendio Montserrat
Published: September 2008

This paper describes and discusses events observed in the Madrid colony of hamadryas and hybrid baboons, when a novel group of 3 adult males, 3 adult females and 1 unweaned infant was introduced to the resident colony comprising 12 adult females, 11 juveniles and 6 unweaned infants. Novel males took over resident adult females in any reproductive condition, and all acyclic females (i.e. lactating, pregnant and immature) exhibited a dramatic enhancement of sexual activity. Lactating females shortened their post-partum amenorrhoea periods and resumed oestrous cycles around day 14 following the introduction of the novel males, without infanticide occurring. Their return to breeding condition was not affected by the age of their current infant or the day they were taken over by the males. A female in an early stage of pregnancy aborted spontaneously and resumed oestrus on day 26. The other pregnant female significantly shortened her gestation time, delivered a viable infant on day 13, and resumed breeding activity 39 days post-partum (on day 52), while suckling her infant. A cycling female adopted and suckled a 74-day-old infant, continued showing oestrous cycles and conceived. Immature females reached menarche significantly earlier than expected and only then joined one of the newly established harem units. It is argued that the observed enhancement of sexual activity was not imposed by the males’ aggressive behaviour but rather was a spontaneous female response to male novelty. This single causal factor was potent enough to override the role that nutrition and lactation normally play in the control of the females’ reproductive activity. Differences in latency until the appearance of the response were probably due to the different constraints imposed by the female’s current reproductive state. It was also hypothesized that when (a) sexual swellings are attractive to males, (b) novel males are especially active in the process of bonding with new females, and (c) males are important sources of coalitionary support, females might by developing sexual swellings compete more successfully against other females and attain a higher position in the female hierarchy of the newly established unit. This would have the ultimate effect of increasing their potential reproductive success. In several cases females did gain socially by coming into oestrus, but attained no immediate reproductive advantage.
The Pairbond in the Titi Monkey (Callicebus moloch): Intrinsic versus Extrinsic Contributions of the Pairmates
Authors: Anzenberger Gustl
Published: September 2008

Aspects of a monogamous relationship can be inferred by observing reactions of mated individuals to unfamiliar conspecifics. The present study examined the behaviours shown by male and female titi monkeys (Callicebus moloch) toward an opposite-sex stranger, and the effect of their pairmate’s absence or presence on these encounters. Behaviours within unfamiliar heterosexual pairs showed superficial similarities to behaviours of mated pairs. Although there were few affiliative behaviours between unfamiliar individuals, animals were often in spatial proximity and even performed sexual behaviour. The visual presence of a pairmate clearly affected encounters between unfamiliar heterosexual pairs in several respects. The presence of a male pairmate had a much stronger influence on all behavioural measures compared to the presence of a female pairmate. Possible functional aspects of these results are discussed.
Activity Patterns in a Captive Group of Celebes Black Ape (Macaca nigra)
Authors: Bernstein Irwin S. , Baker Suzanne C.
Published: September 2008

Both time of day and weather significantly influenced the behavioral activity profile of a captive group of Celebes black apes. There were significant differences when their activity profile was compared to those of stumptail macaques, pigtail macaques, sooty mangabeys and geladas observed under similar conditions. There were, nonetheless several remarkable consistencies, especially among taxonomically related forms. Significant sex differences were also noted for grooming, social interaction rates, self-directed activity, agonistic and sexual behavior. Scores were consistent with data on a second group of black apes and previously reported unusual behavioral categories were confirmed.
Variations in Vocal Patterns of Senegal and South African Lesser Bushbabies and Their Implications for Taxonomic Relationships
Authors: Zimmermann Elke , Bearder Simon K. , Doyle Gerald A. , Andersson Annette B.
Published: September 2008

Vocalizations of Senegal and South African lesser bushbabies were compared with respect to their acoustic properties analysed from spectrograms and oscillograms. Homologous calls could be identified within comparable functional categories. Considerable similarities were revealed in most of the noisy vocalizations associated with aggressive, defensive or anxiety and alarm behaviour. Striking divergences were detected, however, in almost all of the tonal or harmonic call types given in association with contact or contact-seeking, defensive or alarm behaviour. The results provide strong support for the separation of the two forms into distinct species, Galago senegalensis and Galago moholi.
Simplicity and Efficiency of Integrate-and-Fire Neuron Models
Authors: Plesser Hans E. , Diesmann Markus
Published: September 2008

Lovelace and Cios ( 2008 ) recently proposed a very simple spiking neuron (VSSN) model for simulations of large neuronal networks as an efficient replacement for the integrate-and-fire neuron model. We argue that the VSSN model falls behind key advances in neuronal network modeling over the past 20 years, in particular, techniques that permit simulators to compute the state of the neuron without repeated summation over the history of input spikes and to integrate the subthreshold dynamics exactly. State-of-the-art solvers for networks of integrate-and-fire model neurons are substantially more efficient than the VSSN simulator and allow routine simulations of networks of some 105 neurons and 109 connections on moderate computer clusters.
State-Dependent Computation Using Coupled Recurrent Networks
Authors: Rutishauser Ueli , Douglas Rodney J.
Published: September 2008

Although conditional branching between possible behavioral states is a hallmark of intelligent behavior, very little is known about the neuronal mechanisms that support this processing. In a step toward solving this problem, we demonstrate by theoretical analysis and simulation how networks of richly interconnected neurons, such as those observed in the superficial layers of the neocortex, can embed reliable, robust finite state machines. We show how a multistable neuronal network containing a number of states can be created very simply by coupling two recurrent networks whose synaptic weights have been configured for soft winner-take-all (sWTA) performance. These two sWTAs have simple, homogeneous, locally recurrent connectivity except for a small fraction of recurrent cross-connections between them, which are used to embed the required states. This coupling between the maps allows the network to continue to express the current state even after the input that elicited that state is withdrawn. In addition, a small number of transition neurons implement the necessary input-driven transitions between the embedded states. We provide simple rules to systematically design and construct neuronal state machines of this kind. The significance of our finding is that it offers a method whereby the cortex could construct networks supporting a broad range of sophisticated processing by applying only small specializations to the same generic neuronal circuit.
Spike Train Statistics and Dynamics with Synaptic Input from any Renewal Process: A Population Density Approach
Authors: Ly Cheng , Tranchina Daniel
Published: September 2008

In the probability density function (PDF) approach to neural network modeling, a common simplifying assumption is that the arrival times of elementary postsynaptic events are governed by a Poisson process. This assumption ignores temporal correlations in the input that sometimes have important physiological consequences. We extend PDF methods to models with synaptic event times governed by any modulated renewal process. We focus on the integrate-and-fire neuron with instantaneous synaptic kinetics and a random elementary excitatory postsynaptic potential (EPSP), A. Between presynaptic events, the membrane voltage, v, decays exponentially toward rest, while s, the time since the last synaptic input event, evolves with unit velocity. When a synaptic event arrives, v jumps by A, and s is reset to zero. If v crosses the threshold voltage, an action potential occurs, and v is reset to vreset. The probability per unit time of a synaptic event at time t, given the elapsed time s since the last event, h(s, t), depends on specifics of the renewal process. We study how regularity of the train of synaptic input events affects output spike rate, PDF and coefficient of variation (CV) of the interspike interval, and the autocorrelation function of the output spike train. In the limit of a deterministic, clocklike train of input events, the PDF of the interspike interval converges to a sum of delta functions, with coefficients determined by the PDF for A. The limiting autocorrelation function of the output spike train is a sum of delta functions whose coefficients fall under a damped oscillatory envelope. When the EPSP CV, σA/μA, is equal to 0.45, a CV for the intersynaptic event interval, σT/μT = 0.35, is functionally equivalent to a deterministic periodic train of synaptic input events (CV = 0) with respect to spike statistics. We discuss the relevance to neural network simulations.
The Variational Gaussian Approximation Revisited
Authors: Opper Manfred , Archambeau Cédric
Published: September 2008

The variational approximation of posterior distributions by multivariate gaussians has been much less popular in the machine learning community compared to the corresponding approximation by factorizing distributions. This is for a good reason: the gaussian approximation is in general plagued by an [Formula: see text] number of variational parameters to be optimized, N being the number of random variables. In this letter, we discuss the relationship between the Laplace and the variational approximation, and we show that for models with gaussian priors and factorizing likelihoods, the number of variational parameters is actually [Formula: see text]. The approach is applied to gaussian process regression with nongaussian likelihoods.