The suitability of research proposals is assessed by the scientific director of LUPRSF and the animal manager at Furuvik Zoo, in order to determine if research protocols infringe the conditions set by the law, i.e., if the protocols entail invasive procedures or manipulations of the animals' normal environment at the zoo.

**Research Training**

Experimenters received general training from the scientific director of the station and a keeper was present during testing. Subjects were familiar with the experimenter.

**Research Participation**

Subjects engaged voluntarily in testing by entering the experimental room, and were free to leave at any time. Dunja was accompanied by her infant. Both subjects have experience with choice tasks and indicate choices by pointing. A keeper was present during testing who monitored the procedure and distracted the animals not being tested at the time in order to reduce possible interference. For all testing carried out at LUPRSF, the duration and state of each animal is recorded. Specifically, we record how long an individual is engaged in a given task and whether the animal is in a calm, excited, stressed, or agitated state. These records are reported by the scientific director to the Swedish Board of Agriculture, which oversees matters related to animal welfare in Sweden, on a regular basis.

**Other**

The individuals involved in the study form a reproductive group. The female gave birth to an infant in November 2017.
**Monkey Haven, Isle of Wight**

***Background***

The Monkey Haven, Isle of Wight, houses the research facilities of the Macaque Cognition project from the University of Portsmouth (researchers involved: Marine Joly, Bridget Waller, and Jerome Micheletta).

***Animals***

Fifteen primate species, with a total of about 60 individuals, lived at the Monkey Haven during the study. Three rhesus macaques (*Macaca mulatta*) belonging to a group of 5 and 3 Barbary macaques (*Macaca sylvanus*), belonging to a group of 5 were included in this study.

***Enclosures***

The monkeys were housed in enriched enclosures, equipped with climbing structures and enrichment devices (food puzzles, boxes, etc.). They all have access to an outdoor compound. They lived in social groups consisting of 4-6 individuals. Furthermore, only those subjects voluntarily entering the area with the experimental setup participated in the study to ensure low stress levels.

***Diet***

Subjects were never food or water deprived. The monkeys were fed daily with assorted fruits and vegetables, nuts, seeds, and commercial monkey pellets.

***Ethical Approval***

Animal Welfare and Ethical Review Body (AWERB) of the University of Portsmouth

***Research Permission***

The research received approval by the AWERB (approval no. 4015B). All aspects of the study were covered by this ethical approval.

***Research Training***

All individuals were trained by the research staff from the Macaque Cognition Project, University of Portsmouth, under the protocols approved by the AWERB.

***Research Participation***

Cognitive testing required subjects to break from their social group and enter the testing area voluntarily. Only those subjects voluntarily entering the area with the experimental setup participated in the study to ensure low stress levels.

***Other***

Monkeys were monitored daily by research and care staff for psychological and physical wellbeing.
# Paris Zoo

## Background

The zoo, founded in 1934, is part of the National Natural History Museum (MNHN), a vast, multifaceted public institution committed to research, conservation, education and dissemination of knowledge and expertise. Thus, research is engrained in this zoo, and is carried out by its animal curators, students from affiliated universities, and interns from a variety of disciplines.

## Animals

We had thought of testing the MP1 protocol with our two female Guyanan brown capuchins, but given their initial neophobic reaction, and plenty of other factors, such as availability of time, we've switched to woolly monkeys (*Lagothrix lagotricha*). They are 3 males of 13, 14.5 and 19 years old. None of the animals in our zoo have been involved in invasive research nor participated in cognitive studies.

## Enclosures

Our woolly monkeys live in three indoor areas of 10, 10 and 20 m², and have free access to an outdoor enclosure of 330 m². Plenty of tree trunks, branches and ropes create a varying and complex three-dimensional space.

## Diet

Subjects were never food or water deprived. Woolly monkey diet was approved and regularly revised by our vets, and it included fresh vegetables, fruit, and monkey chow. As an incentive for participating in the study, apples, carrots and raisins were used.

## Ethical Approval

Cuvier committee (National Natural History Museum)

## Research Permission

Our zoo is a member of EAZA and complies with all its rules and recommendations regarding animal housing and welfare. Research conducted at the National Natural History Museum needs to be approved by the Cuvier committee - which approved this protocol

## Research Training

Only the primate curator has worked with the animals for this project. Additional participants have observed and might later be involved in the study.

## Research Participation

Animals had no problems accepting the testing platform, and quickly learned to indicate their preference.

Animals normally have access to all three areas of the indoor space. Separating them for the duration of the experiments did not generate tensions, nor did they have to wait for their turn to participate. One session/individual was interrupted as he lost interest in the test, and wanted to play.
*Other*

This is a non-breeding group.
**East China Normal University Primate Research Center**

***Background***

The Primate Center of East China Normal University is located in Shanghai, China.

***Animals***

Over 40 rhesus macaques (*Macaca mulatta*) were housed at the center and 4 males were included in this study.

***Enclosures***

Indoor enclosure (2 m X 1.8 m X 1.8 m) for each rhesus macaque.

***Diet***

As an incentive for participating in the study. Rhesus macaques were fed with fruits, nuts, and monkey chow twice a day. Water was available *ad libitum*.

***Ethical Approval***

East China Normal University Institutional Animal Care and Use Committee (IACUC) gave ethical approval for this study.

***Research Permission***

East China Normal University Institutional Animal Care and Use Committee (IACUC) gave the permission to the MP1 study.

***Research Training***

Experimenters were trained to safely interact with monkeys and practices in accordance with regulations stipulated in the IRB.

***Research Participation***

They were tested in their home cages. Therefore, we consider their participation as voluntary. Animals could decide not to participate in the testing at any time, but they were generally very cooperative.

***Other***

The animals were previously housed in social housing (6 of them) but they were tested in this study in their individual home cages.
**Primate Center of Strasbourg University**

***Background***

The Primate Centre of Strasbourg University is a unique place in Europe, it stretches over seven hectares of wooded land, designed to house primates from nine different species. Geographical isolation and available space provide an ideal setting for studying primates in semi-free ranging conditions. Access to the site is restricted to professionals (i.e., researchers, students, veterinarians, animal caretakers) and state authorities (e.g., veterinary services, Research government department).

***Animals***

The Primate Center of Strasbourg University hosts an average of 700 animals under the supervision of a specialized team of 25 persons (ethologists, researchers, veterinarians, animal caretakers), backed by an animal welfare structure (SBEA) and an independent external ethics committee. Among the different social group of the Primate Centre, we worked on two groups of tonkean macaques (*Macaca tonkeana*) one of the groups was mixed in ages and sexes and composed by 26 individuals and the other one composed by five adult males. We also studied two groups (14 and 5 individuals) of rhesus macaques (*Macaca mulatta*), two groups (15 and 5 individuals respectively) of white-faced capuchins (*Cebus imitator*), one male pair of long-tailed macaques (*Macaca fascicularis*), one male pair of brown capuchins (*Sapajus apella*), two groups (4 and 2 individuals respectively) of green monkeys (*Chlorocebus sabaeus*), one group (5 individuals) of brown lemurs (*Eulemur fulvus*), one female pair of black lemurs (*Eulemur macaco*), and two Families (4 and 6 individuals) of common marmosets (*Callithrix jacchus*). However, animals participated voluntary to the experiment and thus not all groups' members could participate in the task. Thirty-six individuals were tested. None of the tested individuals is involved in invasive research.

***Enclosures***

Most of the tested groups live in semi-free ranging conditions in wooded parks (3000 to 5000 m²) with permanent access to an indoor-outdoor shelter (10 to 20 m²). The other smallest groups live in indoor-outdoor shelters (20 to 50 m²).

***Diet***

Subjects were never food or water deprived. Individuals were fed with commercial primate pellets twice a day in the indoor shelter and received fresh fruit and vegetables once a week. Water was provided *ad libitum* in the indoor shelter. Each reward corresponded to 0.5% of the daily caloric intake, if the individuals were able to accumulate the maximum number of rewards in both trials it corresponded to 10% of the daily caloric intake.

***Ethical Approval***

In France, official approval is not requested for ethological studies based on animal volunteering. However, the Primate Centre (Silabe) has its own authorization for housing and breeding NHP (n°B6732636).

***Research Permission***

Research complied with the EU Directive 2010/63/EU for animal experiments
## Research Training

Data were collected by PhD and master students with experience in designing and performing behavioral assessments with different primate species. Most of the experimenters had conducted previous research at different institutions and were familiar with the husbandry and safety procedures of the primate center. For those less experienced, permanent experienced researchers of the Primate Centre of Strasbourg University taught and trained them to safely interact with monkeys and not give them subtle behavioral cues.

## Research Participation

All subjects participated voluntarily. They were free to stop and leave the experimental area at any time, even in the middle of a session or trial. Most of the individuals were tested in a special area for behavioral experiments (SAS). However, some individuals were tested in the park because they did not want to work in the SAS. All monkeys were highly motivated to participate.

## Other

All tested subjects lived in multi-male/multi-female social groups or families (for marmosets) except two males brown capuchins living together without female and one of the Tonkean macaque living in a five males group.
# Primate Station of the Department of Anthropology of the University of Zurich

## Background

The Primate Station of the Department of Anthropology of the University of Zurich is situated at the Irchel campus in Zurich city. The station contains 31 indoor enclosures and 20 outdoor enclosures. In addition, the house contains heaters and humidifiers to simulate tropical conditions.

## Animals

Seventy-two common marmosets (*Callithrix jacchus*) and 9 cotton top tamarins (*Saguinus oedipus*) were housed at Primate Station. A total of 16 common marmosets (3 family groups and 3 couples) were included in this experiment. No animal of Primate Station is involved in invasive research (all experiments are licensed at degree of severity = 0).

## Enclosures

Their home enclosures are 2.5 m height X 1.8 m width X 3.5 m depth and are enriched with several climbing structures such as natural branches and ropes. Each enclosure contains an infrared lamp and a sleeping box. The floor is covered with bark mulch. The enclosures of the two couples are slightly smaller (2 m height X 1 m width X 3 m depth). Additionally, each group has access to an outdoor enclosure (2.5 m height X 1.8 m width X 3.5 m depth) which also contains structures as natural branches and ropes, climbing structures and soil with natural plants. During summertime and whenever the weather allows it (temperature above 10 degree), the animals have access to the outdoor part. These two parts are connected via a tunnel system.

## Diet

Subjects were never food or water deprived. The marmosets were fed a porridge containing vitamin supplements in the morning and fresh fruits and vegetables around midday. Each afternoon, they received a protein snack such as mealworms or a piece of boiled egg. Regular diet was given at the same time and the same place as usual. Water is available ad libitum from water dispensers. The changes made in their routine living conditions were kept to a minimum and only if essential to the experiment.

## Ethical Approval

Veterinary Office of the Canton of Zurich

## Research Permission

Licensed by the Kantonales Veterinäramt ZH, license number ZH232/19; degree of severity = 0

## Research Training

Experimenters receive theoretical and practical training held by Institute of Laboratory Animal Sciences (LTK) and it is accredited by FELASA (Federation of European Laboratory Animal Science Associations) and the Federation of Swiss Cantonal Veterinary Officers (VSKT). This course is approved by the Federal Food Safety and Veterinary Office as official education in Switzerland for experimenters and is also accredited by the FELASA according to the functions of the EU Directive (functions A, C, D and modules 10, 20, 21).
Research Participation

The animals participated on voluntary basis, i.e., they were not handled but trained to enter the experimental cages voluntarily. If they showed signs of distress (e.g., piloerection of the tail, trying to leave the test situation) the experiment stopped and was continued the next day.
**Texas Biomedical Research Institute**

***Background***

Texas Biomedical Research Institute in San Antonio, Texas, is home to the Southwest National Primate Research Center (SNPRC). Founded in 1941 by Thomas B. Slick, the institute aims to protect the global community through pioneering research and scientific discovery while maintaining the wellbeing of our animal models. In 1999, the SNPRC became the first new NPRC in more than 35 years. The 200-acre campus is home to over 2,200 primates. This includes the largest baboon population (around 1,000) in North America and the largest marmoset population (around 500) in the world dedicated to infectious disease and aging research.

***Animals***

Texas Biomedical Research Institute houses several primate species including macaques, vervets, capuchins, baboons, marmosets, and retired chimpanzees. For this study, the SNPRC contributed data from 6 individual baboons (*Papio anubis*). None of the animals tested in this study were involved in invasive research.

***Enclosures***

Study subjects for this project are housed in outdoor group housing of varying size. Animals have access to manipulable and structural enrichment at all times. The enclosures are equipped with climbing structures, perches, hanging barrels, visual panels, and cage toys. Nutritional enrichment is provided at least five times a week. Social groups consist of 2-12 individuals.

***Diet***

Subjects were never food or water deprived. Our animals received a veterinarian-approved diet. Supplement enrichment was provided no less than five times a week. Water was available *ad libitum*. The food rewards used as an incentive for participating in this study were counted as part of the animals' enrichment for that day.

***Ethical approval***

This research was approved by the IACUC of Texas Biomedical Research Institute. Texas Biomedical Research Institute is accredited by the Association for Assessment and Accreditation of Laboratory Animal Care International.

***Research Permission***

Colony use protocols for both rhesus and baboons are approved by the IACUC committee. The procedures required for this study can be classified as occupational and nutritional enrichment according to our guidelines, which is covered under the animal's current protocols. A research request for this specific study was submitted and approved by the Texas Biomed IACUC.

***Research Training***

Research was conducted by an SNPRC behaviorist that worked closely with the tested subjects on a daily basis. Animals were trained by behavioral services staff at the SNPRC under standard operating procedures approved by the IACUC.
Research Participation

Animal participation was completely voluntary. No participation was ever coerced. Individuals
were not separated from conspecifics during study sessions, but willingly separated from the group at their
own comfort level. If an animal showed signs of distress during the test, testing was halted immediately.

Other

The animal's physical and psychological well-being was monitored daily by care staff.
# Wolfgang Köhler Primate Research Center

## Background

The Wolfgang Köhler Primate Research Center (WKPRC) is a project of the Max Planck Institute for Evolutionary Anthropology. It is operated in collaboration with the Leipzig Zoo. Research focuses on the behavior and cognition of the four species of great ape: chimpanzees (*Pan troglodytes*), gorillas (*Gorilla gorilla*), orangutans (*Pongo pygmaeus*), and bonobos (*Pan paniscus*). Researchers and students from the University of Leipzig, and other universities around the world, conduct their research projects at the center guided by the personnel of the Center.

## Animals

Eleven chimpanzees and 5 orangutans participated in this study. The chimpanzees sample consisted of 7 females (age range 16-42) and 4 males (age range 14-43); the orangutan sample consisted of 4 females (15-30) and one male (38). All individuals lived in social groups.

## Enclosures

The indoor space featured climbing structures, wooden platforms, visual barriers. The outdoor space had a grass floor, climbing trees, wooden platforms, and visual barriers. They had access to their outdoor exhibit area whenever weather permitted. The total size of the indoor/outdoor enclosure was 430/4000 m² for the chimpanzees and 230/1680 m² for the orangutans. Both enclosures are equipped with shaking boxes and poking bins which allow the apes to engage in activities similar to their natural social and foraging behaviors (e.g., tool use).

## Diet

Subjects are never deprived of food or water. The chimpanzees and orangutans were fed with a variety of fresh fruit and vegetables daily. The food rewards that were used as an incentive for participating in this study (grapes) were reviewed and approved by veterinary and nutrition staff prior to the start of the experiment. In addition, the apes regularly received special foods (e.g., chestnuts) that the keepers hid in certain areas of the enclosure to promote natural foraging activities. Other opportunities for special foraging activities (e.g., artificial termite mounds) were offered on a regular basis and special enrichment materials were provided for the apes every afternoon.

## Ethical Approval

The study was ethically approved by the internal ethics committee of the Max Planck Institute for Evolutionary Anthropology and Leipzig Zoo. Members of the committee are: director of the WKPRC, Dr. J. Call, research coordinator at WKPRC, Dr. D. Hanus, zoo veterinarian, Dr. A. Bernhard, head animal keeper, F. Schellhardt, and assistant head animal keeper, M. Lohse. All research at WKPRC is approved by this committee. No medical, toxicological, or neurobiological research of any kind is conducted at the WKPRC. Research was non-invasive and strictly adhered to the legal requirements of Germany. Animal husbandry and research comply with the "EAZA Minimum Standards for the Accommodation and Care of Animals in Zoos and Aquaria", the "WAZA Ethical Guidelines for the Conduct of Research on Animals by Zoos and Aquariums" and the "Guidelines for the Treatment of Animals in Behavioral Research and Teaching" of the Association for the Study of Animal Behavior (ASAB).
## Research Permission

Permission was given by an internal committee of the Max Planck Institute for Evolutionary Anthropology and the Leipzig Zoo (see above). No permit number was issued. Further IRB/IAUCUC approval was not necessary because no special permission for the use of animals in purely behavioral or observational studies is required in Germany (TierSchGes §7 and §8).

## Research Training

The researchers are all employees of the Max Planck Institute. The keepers are all employees of Leipzig Zoo and so have received extensive training working with these animals.

## Research Participation

All individuals were tested individually. Only those subjects voluntarily entering the area with the experimental setup participated in the study and a session would be stopped if a subject showed any sign of distress.

## Other

In cooperation with the zoo, the Köhler Center supports efforts to conserve great apes, both in the wild and in captivity. The breeding program at the zoo is framed within the global strategy of the EEP, and some research focuses on the husbandry and care of great apes in captivity.
# Wuhan Zoo

## Background

Wuhan zoo is located in Wuhan, Hubei Province, China. It was first open to the public in 1985. It was founded and funded by the city government.

## Animals

Francois's langurs (*Trachypithecus francoisi*) (2 females and 4 males).

No invasive research has ever been conducted at the zoo.

## Enclosures

For Francois's langurs: indoor enclosure (32 m²), outdoor enclosure (~35m²). They live in a social group of 6, with free access between indoor and outdoor enclosures.

## Diet

Subjects were never food or water deprived. The Francois's langurs daily diet included leaves, fruits, steamed buns and a small quantity of nuts. As an incentive for participating in the study, nuts and dates (both are part of their normal diet) were used.

## Ethical Approval

The zoo's management approved their own caretakers to run study on their own animals.

## Research Permission

See above.

## Research Training

No systematic training. The animals were only trained (via positive reinforcement) to come when their names were called.

## Research Participation

Testing happened in the indoor enclosure. The door to the outdoor enclosure was always open. Subjects could exit freely anytime.
# Zoo Leipzig

## Background

The Max Planck Institute for Evolutionary Anthropology conducts research on primate behavior and cognition in collaboration with the Leipzig Zoo. Besides the well-established Wolfgang Köhler Primate Research Center (WKPRC), which focuses on the four great ape species housed in “Pongoland”, the Max Planck Institute also conducts research on other primates as part of the ManyPrimates project. This includes the following four species: Diana monkeys (*Cercopithecus diana*), Hamlyn's monkeys (*Cercopithecus hamlyni*), crowned lemurs (*Eulemur coronatus*), and golden lion tamarins (*Leontopithecus rosalia*).

## Animals

Five Diana monkeys, four Hamlyn's monkeys, two golden lion tamarins, and three crowned lemurs participated in this study. The Diana monkey sample consisted of four females (age range 1-13) and one male (age 14); the Hamlyn's monkey sample consisted of four individuals housed in two separated groups: group 1) two males (3 and 10), group 2) one female (23) and one male (15); the golden lion tamarin sample consisted of one female (5) and one male (8); the crowned lemur sample consisted of two females (1 and 5) and one male (6). All individuals lived in social groups.

## Enclosures

Three species, Diana monkeys, group 1 of the Hamlyn's monkeys, and crowned lemurs were housed in “Gondwanaland”, a massive greenhouse with a tropical climate. Group 2 of the Hamlyn's monkeys were housed in rear animal husbandry, meaning that enclosures were not visible for visitors. During the time of the study, the golden lion tamarins were also housed in rear animal husbandry, as the female golden lion tamarin only recently moved to the Leipzig Zoo.

All three species in Gondwanaland had two enclosures: one serving as sleeping space/rear enclosure and one outside enclosure, from which the animals are visible to visitors. The sleeping spaces of all three species featured climbing structures and platforms. The times, when the animals were in the outdoor space typically correlated with the opening times of the Zoo.

The Diana monkeys shared their outdoor space with pygmy hippopotamuses (*Choeropsis liberiensis*). It featured climbing structures, platforms, and visual barriers. The total size of sleeping space/outdoor space was 45 m²/230 m².

Group 1 of the Hamlyn's monkeys shared their outdoor space with Kirk's dik-diks (*Madoqua kirkii*). It featured climbing structures, platforms, and visual barriers. The total size of sleeping space/outdoor space was 27 m²/100 m².

The crowned lemurs shared their outdoor space with radiated tortoises (*Astrochelys radiate*). It featured climbing structures, platforms, and visual barriers. The total size of sleeping space/outdoor space was 25 m²/110 m².

Group 2 of the Hamlyn's monkeys had an indoor and outdoor space. It featured climbing structures and platforms. They had access to their outdoor area when weather permitted. The total size of indoor and outdoor space was 18 m²/25 m².

The golden lion tamarins were housed in an indoor and outdoor space not visible to visitors. Both indoor and outdoor space featured climbing structures and platforms. They had access to their outdoor area when weather permitted. The total size of sleeping indoor/outdoor space was 17 m²/10 m².

## Diet

Subjects were never food or water deprived. The Diana monkeys and Hamlyn's monkeys were fed with a variety of fruit and other food, such as cooked meat, seeds, dried fruit, vegetables, and salad. The
Golden lion tamarins were mainly fed with a variety of fresh vegetables, small amounts of fruits, cooked meat, eggs, insects, and gum arabic as a surrogate for tree sap. In addition, the monkeys regularly received food that the keepers hid in certain areas of the enclosure to promote natural foraging activities and enrichment materials. The crowned lemurs were fed with a variety of fresh vegetables and other food, such as salad, insects, leaves, and small amounts of fresh fruit. All food rewards that were used as an incentive for participating in the study were reviewed and approved by veterinary and nutrition staff prior to the start of the experiments.

## Ethical Approval

The study was ethically approved by the internal ethics committee of the Max Planck Institute for Evolutionary Anthropology and Leipzig Zoo. Members of the committee were: research coordinator at WKPRC, Dr. D. Hanus, zoo veterinarian, Dr. A. Bernhard, head animal keeper, F. Schellhardt, and assistant head animal keeper, M. Lohse. No medical, toxicological, or neurobiological research of any kind is conducted at Leipzig Zoo. Research was non-invasive and strictly adhered to the legal requirements of Germany. Animal husbandry and research comply with the “EAZA Minimum Standards for the Accommodation and Care of Animals in Zoos and Aquaria”, the “WAZA Ethical Guidelines for the Conduct of Research on Animals by Zoos and Aquariums” and the “Guidelines for the Treatment of Animals in Behavioral Research and Teaching” of the Association for the Study of Animal Behavior (ASAB).

## Research Permission

Permission was given by an internal committee of the Max Planck Institute for Evolutionary Anthropology and the Leipzig Zoo (see above). No permit number was issued. Further IRB/IAUCUC approval was not necessary because no special permission for the use of animals in purely behavioral or observational studies is required in Germany (TierSchGes §7 and §8).

## Research Training

The researchers are all employees of the Max Planck Institute. The keepers are all employees of Leipzig Zoo and so have received extensive training working with these animals.

## Research Participation

Most subjects could be tested individually; only the young Diana monkeys had to be with their mother while testing. Sessions would be stopped if a subject showed any sign of distress.
**Zoo Schönbrunn**

***Background***

The complete name of the zoo is Tiergarten Schönbrunn and is located on the grounds of the Schönbrunn Palace in Vienna, Austria. It is the oldest continuously operating zoo in the world. The zoo houses a total of 10 primate species.

***Animals***

Tiergarten Schönbrunn houses three adult Bornean orangutans (*Pongo pygmaeus*; 2 females, one male).

***Enclosures***

The indoor area features climbing structures, wooden platforms, visual barriers. The outdoor space has a grass floor, climbing trees, wooden platforms, and visual barriers. Orangutans have access to their outdoor exhibit area whenever weather permits. The total size of the indoor/outdoor enclosure was 167/745 m². Both enclosures are equipped with enrichment devices such as shaking boxes and poking bins, which allow the apes to engage in activities similar to their natural social and foraging behaviors (e.g., tool use).

***Diet***

Subjects were never food or water deprived. The orangutans were fed on a varied diet of vegetables, fruit, yoghurt, seeds, and vegetation. They were fed three times a day and they received regular food through enrichment devices and research rewards.

***Ethical Approval***

Discussed and approved by the institutional ethics and animal welfare committee of the University of Veterinary Medicine Vienna (Austria) in accordance with GSP guidelines and national legislation (project entitled “The evolutionary origins of short-term memory in primates: a ManyPrimates project” was approved on 28/10/2019; permit number ETK-167/10/2019).

***Research Permission***

The project has been approved by the research and conservation manager and the deputy zoo director of the Tiergarten Schönbrunn. The research project has ethical approval from the lead researcher's institution.

***Research Training***

The research has been carried out by a trained animal caretakers of the Tiergarten Schönbrunn in close collaboration with the lead researcher who has experience in designing and performing cognitive tests with different primate species.

***Research Participation***

The participation in the test was completely voluntary. The test was conducted while the apes were in their sleeping rooms as an enrichment activity early in the morning before the apes got access to their indoor enclosure. All apes were willing to participate in the tests, and did not show any signs of stress.
**Supplemental References**

Buchanan-Smith, H. M. Griciute, J., Daoudi, S., Leonardi, R., & Whiten, A. (2013). Interspecific interactions and welfare implications in mixed species communities of capuchin (*Sapajus apella*) and squirrel monkeys (*Saimiri sciureus*) over 3 years. *Applied Animal Behaviour Science*, *147*(3-4), 324-333.

Lonsdorf, E. V., Bonnie, K. E., Grim, M., Krupnick, A., Prestipino, M., Whyte, J. (2016). Social influences on the spread of arbitrary conventions among capuchin monkeys. *Behaviour*, *153*, 633-654.

Macdonald, C. & Whiten, A. (2011). The ‘Living inks to Human Evolution’ Research Centre in Edinburgh Zoo: A new endeavour in collaboration. *International Zoo Yearbook*, *45*(1), 7–17.