Presenter 1 ： David Fasbender

Title：  Assessing the distribution and Ecology of the Bonobos of the Lomami National Park with a Combination of Indirect Methods
Language:   English (Slides & Talk)

PhD thesis concept presentation

Abstract： As one of our closest relatives that share with us many unique social tendencies, bonobos (Pan paniscus) play an important role in understanding hominin social evolution. Like our ancestors bonobos are large-bodied social primates that feed primarily on ripe fruit, a patchy and seasonal resource. Therefore, their grouping patterns and social organization are generally considered in the context of food competition. Here, a first study tested whether seasonal food scarcity affects bonobo social organization. At a new study site camera traps were deployed to record bonobo groups (parties) with concurrent fruit surveys for one year. This revealed a small impact of fruit distribution on bonobo party size but no impact on female-gregariousness, a unique feature of bonobo fission-fusion grouping patterns. A second study examined the foraging patterns of habituated bonobos at Wamba to see if bonobos target fruits with characteristics associated with lower competition. Ecological characteristics of all consumed fruits were measured to determine if bonobo parties move is more rapid and linear manner towards short lasting, synchronous fruits and spatially clustered fruits in larger patches. Despite data limitations, this study found rapid linear movement towards certain favorite and short-lasting foods, supporting bonobo selectivity in foraging. Such spatially-targeted group mobility indicates a foraging strategy that could potentially help explain the stable social cohesiveness of foraging bonobo groups. Together these studies found that social features such as female gregariousness are resilient to fruit seasonality contrary to predictions of food competition and that bonobos feed in a selective goal-oriented manner that might facilitate such sociality.  .

Presenter 2： Rentaro Kimpara

Title：  Relationship between contact calls and group cohesion in Japanese macaques in Yakushima Island
Language:   Slides (English) and Talk (Japanese)
Abstract：In this presentation, I will report on the progress of my master's research and this year's research plans. Keeping Group cohesion is important for receiving the benefit of group living. Vocal communication is effective for primates living in visually poor environments such as forests. On Yakushima Island, contact calls appear to play an important role in maintaining group cohesion due to the low visibility of the habitat. However, it is unclear whether contact calls could affect group cohesion in Japanese macaques. In my master’s research, we will investigate the relationships between contact calls and group cohesion. Preliminary research was conducted between October and December last year. After identifying individuals, behavioral data and vocal data were collected from females over 5 years of age. We analyzed group cohesion using the same method as the previous research. In addition, a recent vocal individual identification method was applied to three individuals. The results showed that group cohesion was somewhat different from the previous study.  Moreover, the possibility was suggested that individuals could be identified from the contact calls. Data collection is planned for May-July and September-November and these plans will also be presented.

1: General instruction about presentations and participation in the seminar, by Mitani-sensei

2: Itahara-san's presentation

3: Hirata-sensei's presentation 

Please note: We will have Mitani-sensei's Orientation about WRC seminars before presentations.

2024年4月9日(火)　13:15～ @seminar room + zoom

Date: 9th April.  (Tue)  13:15-  @seminar room + zoom 

Presenter 1 ： Akihiro Itahara

Title： Gaze tracking of large-billed crows (Corvus macrorhynchos) in a motion capture system
Language:   English
Abstract：Previous studies often inferred the focus of a bird's attention from its head movements because it provides important clues about their perception and cognition. However, it remains challenging to do so accurately, as the details of how they orient their visual field toward the visual targets remain largely unclear. We thus examined visual field configurations and the visual field use of large-billed crows (Corvus macrorhynchos Wagler 1827). We used an established ophthalmoscopic reflex technique to identify the visual field configuration, including the binocular width and optical axes, as well as the degree of eye movement. A newly established motion capture system was then used to track the head movements of freely moving crows to examine how they oriented their reconstructed visual fields toward attention-getting objects. When visual targets were moving, the crows frequently used their binocular visual fields, particularly around the projection of the beak-tip. When the visual targets stopped moving, crows frequently used non-binocular visual fields, particularly around the regions where their optical axes were found. On such occasions, the crows slightly preferred the right eye. Overall, the visual field use of crows is clearly predictable. Thus, while the untracked eye movements could introduce some level of uncertainty (typically within 15 deg), we demonstrated the feasibility of inferring a crow's attentional focus by 3D tracking of their heads. Our system represents a promising initial step towards establishing gaze tracking methods for studying corvid behavior and cognition. In this talk, I will briefly discuss the results from my previous experiments on communication through gaze, gaze following, and anticipatory looking.

Presenter 2： Satoshi Hirata

Title： Measuring heart rate in captive chimpanzees without anesthesia
Language:   English and Japanese
Abstract：I will explain about one of my recent studies, an abstract of

which is pasted below, and also explains about the process of writing and

submitting a manuscript for a scientific journal.

Heart rate measurements can be a useful way to monitor both physical and mental condition in human and nonhuman animals. Yet, information about heart rate in chimpanzees, who are phylogenetically the closest species to humans, is scarce. Existing data about chimpanzee heart rate have mainly been collected from chimpanzees under anesthesia. To address this issue, we conducted electrocardiogram recordings in captive chimpanzees under normal conditions without anesthesia based on positive reinforcement husbandry training. We obtained a total of 771 recordings from 35 individuals (22 males and 13 females, 14¬–53 years old) with no cardiac problems. The results showed that females had a higher heart rate than male chimpanzees, and that heart rate decreased as a function of age. In addition, heart rate was lower in the morning and increased during the day. Overall, the mean heart rate of adult males was 86.5 beats/min, and that of female chimpanzees was 106.4 beats/min. Our data could serve as a reference point for future research and health-based monitoring of chimpanzee heart rate.