Chimpanzee Kanako

Chimpanzee societies generally show male philopatry and female dispersal. However, demographic data on wild chimpanzee societies from long-term study sites have revealed that some females give birth in their natal group (i.e., “remaining females”). Here, we report two remaining females in the M group in Mahale, Tanzania, and compare their cases with previous reports to explore the social and ecological factors that lead to females remaining in their natal group. The results revealed that neither the social traits of the remaining females nor the ecological factors they experienced showed a coherent trend. However, we found multiple, non-mutually exclusive potential factors that may infuence the decision by females to remain in their natal group: a decrease in indirect feeding competition, support from mothers or allomothers in the care of ofspring and in aggressive interactions with other individuals, close relationships with the other remaining females, and a short adolescent infertility period. Additionally, we observed a natal female copulating with her older brother, which was the frst observation of brother–sister incest in Mahale. Although DNA analysis revealed that her infant was not a product of inbreeding, the pair copulated frequently in the latter half of her estrus period, suggesting that they did not avoid incest behaviorally to avoid inbreeding. Furthermore, there was no hard evidence that the remaining female avoided mating with her maternal brother, suggesting that incest avoidance may not be a proximate factor responsible for female dispersal

Fake snakes uncover chimpanzees’ mind-reading ability

Crockford et al. (2017, Science Advances, 3(11), e1701742) conducted experimental studies in the wild in Africa to investigate the ability of chimpanzees to understand the mental states of other conspecific individuals. Their findings suggest that chimpanzees understand whether or not other individuals are aware of dangers, and they behave differently according to their understanding about the mental states of other individuals

Does size matter? Examining the possible mechanisms of multi-stallion groups in horse societies

In some feral horse populations, adult females are either associated with a single male or multiple males (stallions). However, little is known on why such groups with more than one male exist, considering that stallions fight to monopolize females. Body size is often an important determinant of male fighting ability and/or dominance rank and, consequently, reproductive success. Stallions may, therefore, vary in “quality” which could be a differentiating factor between single-stallion and multi-stallion males. We observed feral Garrano horses in Northern Portugal and examined the relationship between body size, sex, group type and number of females. Using a non-invasive laser distance meter, we determined individual body length and height by overlapping photos of the horses and a measuring tape. We tested the accuracy of remote measurements by comparison with manually measuring domestic horses and found no statistical differences between the two methods. Thus, we assume the values obtained were reliable and the methodology used was a useful tool for assessing morphological characteristics. Results showed no significant differences in body length and height for all parameters assessed, suggesting that size is not a determinant factor for feral horse society. Thus, other factors may be more important to explain the existence of single and multi-stallion groups

Spontaneous attention and psycho-physiological responses to others’ injury in chimpanzees

他者の怪我に対しチンパンジーが情動的に反応することを発見 --最新技術が明かす類人猿の注意と生理的反応--. 京都大学プレスリリース. 2019-06-19.Previous studies have shown that humans experience negative emotions when seeing contextual cues of others’ pain, such as injury (i.e., empathic pain), even without observing behavioral expressions of distress. However, this phenomenon has not been examined in nonhuman primates. We tested six chimpanzees (Pan troglodytes) to experimentally examine their reactions to others’ injury. First, we measured viewing responses using eye-tracking. Chimpanzees spontaneously attended to injured conspecifics more than non-injured conspecifics, but did not do so in a control condition in which images of injuries were scrambled while maintaining color information. Chimpanzees did not avoid viewing injuries at any point during stimulus presentation. Second, we used thermal imaging to investigate chimpanzees’ physiological responses to others’ injury. Previous studies reported that reduced nasal temperature is a characteristic of arousal, particularly arousal associated with negative valence. We presented chimpanzees with a realistic injury: a familiar human experimenter with a prosthetic wound and artificial running blood. Chimpanzees exhibited a greater nasal temperature reduction in response to injury compared with the control stimulus. Finally, chimpanzees were presented with a familiar experimenter who stabbed their (fake) thumb with a needle, with no running blood, a situation that may be more challenging in terms of understanding the cause of distress. Chimpanzees did not physiologically distinguish this condition from the control condition. These results suggest that chimpanzees inspect others’ injuries and become aroused by seeing injuries even without observing behavioral cues, but have difficulty doing so without explicit (or familiar) cues (i.e., open wound and blood)

Non-contact respiratory measurement in a horse in standing position using millimeter-wave array radar

飼育ウマの呼吸数を非接触で測定することに成功 --ミリ波レーダを用いた非接触バイタル測定技術の確立へ--. 京都大学プレスリリース. 2022-08-10.This study aimed to apply radar technology to a large quadruped animal. We first developed a non-contact respiration measurement system using millimeter-wave array radar for a horse in standing position. Specifically, we measured the respiration of a stationary domestic horse in stables. Simultaneously, we measured the respiration rate using infrared thermography and developed a method for analyzing the radar information while verifying the rate of agreement. Our results suggested that the radar technology detected breathing and accurately measured the respiration of a horse, despite variation in the breathing frequency. To the best of our knowledge, this is the first study to apply a non-contact respiration measurement system using millimeter-wave array radar has been applied to large animals in an upright position, thereby demonstrating its potential application in animal husbandry and welfare

シャカイテキ バメン ニ オケル チンパンジー ノ コウドウ ト ニンチ

本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである京都大学0048新制・課程博士博士(理学)甲第8798号理博第2370号新制||理||1230(附属図書館)UT51-2001-F128京都大学大学院理学研究科生物科学専攻(主査)教授 松沢 哲郎, 教授 上原 重男, 助教授 友永 雅己学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDFA

Eye tracking uncovered great apes' ability to anticipate that other individuals will act according to false beliefs

Financial support came from Ministry of Education, Culture, Sports, Science and Technology (K-CONNEX to FK), Japan Society for Promotion of Science (KAKENHI 26885040, 16K21108 to FK), National Science Foundation (DGE-1106401 to CK), JSPS (KAKENHI 26245069, 24000001 to SH), and European Research Council (Synergy grant 609819 SOMICS to JC)Using a novel eye-tracking test, we recently showed that great apes anticipate that other individuals will act according to false beliefs. This finding suggests that, like humans, great apes understand others' false beliefs, at least in an implicit way. One key question raised by our study is why apes have passed our tests but not previous ones. In this article, we consider this question by detailing the development of our task. We considered three major differences in our task compared to the previous ones. First, we monitored apes' eye movements, and specifically their anticipatory looks, in order to measure their predictions about how agents will behave. Second, we adapted our design from an anticipatory-looking false belief test originally developed for human infants. Third, we developed novel test scenarios that were specifically designed to capture the attention of our ape participants. We then discuss how each difference may help explain differences in performance on our task and previous ones, and finally propose some directions for future studies.Publisher PDFPeer reviewe