A plain explanation of my works in graduate school.
A plain explanation of my works in graduate school.
Short description of portfolio item number 1
Short description of portfolio item number 2
Published in American Journal of Primatology, 2017
Accelerometers have been used to study both terrestrial and aquatic wildlife, mainly for mammal and bird species. In terrestrial mammals, there is a bias toward ungulates and carnivores, with fewer studies on nonhuman primates. In this study, we tested the use of accelerometers for studying the activity of Japanese macaques (Macaca fuscata). We modeled the activity of a male and a female subject by matching continuous focal observations from video recordings to sensor parameters derived from collar-mounted accelerometers. Models achieved classification performance (AUC) of greater than 90% for both subjects, with similar results when subjects were cross-validated. Accelerometer-based estimates of activity had comparable accuracies to estimates from instantaneous sampling at 1?min and 5?min intervals. We further demonstrated the use of model estimates for analyzing circadian rhythm and night time activity of M. fuscata. Our results add support to the feasibility of using accelerometers for studying activity of nonhuman primates. We discussed the limitations, benefits and potential applications of remote-sensing technology like accelerometers for advancing primalotogical studies.
Recommended citation: Sha, J. C. M., S., Akihisa, K., Naoko, S.-H., He, T., Makiko, T., Zhang, P., & Hanya, G. (2017). Estimating activity of Japanese macaques (Macaca fuscata) using accelerometers. American Journal of Primatology, 79(10), e22694. https://doi.org/10.1002/ajp.22694 https://doi.org/10.1002/ajp.22694
Published in Mammal Study, 2017
We aimed to validate a method to identify age class and sex of sika deer (Cervus nippon), which defecate fecal pellets. We collected 42 and 54 fecal samples in Nara and Yakushima, respectively. Both pellet width and length were significantly larger for adults than juveniles (1~1.5 yrs). A discriminant model based on both width and length correctly assigned an age class for 92% of individuals in Nara and 98% in Yakushima. We genetically determined their sex based on the gel electrophoresis of two genes on sex chromosomes (SRY and ZFX/Y) amplified by PCR. For fresh feces, sex was not determined for 40% of the samples, but for the rest of the samples, sex was correctly assigned in almost all cases (28/29). However, sex was not determined in any of the samples that were analyzed at a half month or later after defecation. The proportion of young individuals could be estimated by the morphometry of fecal pellets, but the sex of the animals could not be confirmed.
Recommended citation: Hanya, G., Naito, S., Namioka, E., Ueda, Y., Sato, Y., Pastrana, J. A., He, T., Yan, X., Saito, M., Costa, R. F. P., Allanic, M., Honda, T., Kurihara, Y., Yumoto, T., & Hayakawa, T. (2017). Morphometric and genetic determination of age class and sex for fecal pellets of sika deer (Cervus nippon). Mammal Study, 42(4), 1-8. https://doi.org/10.3106/041.042.0406
Published in Journal of Thermal Biology, 2018
Animals living in seasonal environments must adapt to a wide variation of temperature changes which requires flexible adjustments of time budget and metabolic processes for efficient thermoregulation. The Japanese macaque (Macaca fuscata) is one of only a handful of nonhuman primate species that experience seasonal climates over a wide temperature range. We used behavior observations, accelerometer sensors and the doubly-labelled water (DLW) method to measure activity and total daily energy expenditure (TDEE) of M. fuscata housed in captivity but exposed to natural seasonal variations at day lengths ranging from 10 to 12 h and temperature ranging from 0 to 32C. Although overall activity was significantly lower in winter compared to summer and autumn, we found no effect of temperature on day-time activity. However nocturnal inactivity and mean length of sleeping bouts significantly increased along a gradient of decreasing temperatures from summer through winter, suggesting the importance of adaptive behavioral thermoregulation in this species. Energy expenditure that was unaccounted for by Basal Metabolic Rate (BMR) and physical activity i.e. expended through diet-induced thermogenesis or thermoregulation was between 14% and 32%. This residual energy expenditure differed between summer/autumn and winter and was relatively consistent across individuals (approximately 5-8% higher in winter). The percentage of body fat and residual energy expenditure were negatively correlated,
Recommended citation: Sha, J. C. M., Kurihara, Y., Tsuji, Y., Take, M., He, T., Kaneko, A., Suda-Hashimoto, N., Morimoto, M., Natsume, T., Zahariev, A., Blanc, S., & Hanya, G. (2018). Seasonal variation of energy expenditure in Japanese macaques (Macaca fuscata). Journal of Thermal Biology, 76, 139-146. https://doi.org/10.1016/j.jtherbio.2018.07.009
Published in American Journal of Physical Anthropology, 2020
Objectives: Chewing efficiency plays an important role in the survival and distribution of primates. Yet, little is known about the intra-specific variation of chewing efficiency. The purpose of this study is to report the pattern of seasonal and regional variation in chewing efficiency among Yakushima Japanese macaques (Macaca fuscata yakui). Materials and Methods: Fecal samples of Yakushima Japanese macaques were collected from lowland, highland and summit areas in Yakushima between July 2015 and March 2016 (n = 236). Using sieving analysis, we compared fecal particle size (dMEAN) and proportion of finest particles p(0) between different geographical areas and seasons. Results: Seasonally, in the lowland zone, there was a non-significant decrease in dMEAN during spring, while p(0) was significantly higher during summer than it was during winter and spring. Regionally, dMEAN was higher in the summit zone than it was in other areas during autumn, while p(0) was also higher in the summit zone. Conclusions: While seasonal variation in dMEAN can be explained by the reported difference in the proportions of food categories in diet between seasons, its influence is mitigated, possibly by the selective feeding of less mechanically challenging parts in each category. Regional variation in dMEAN and p(0) may be the results of bamboo consumption in this area. Combining our data with studies that focus on seasonal and regional variations of food properties or gut microbes might provide a better understanding of the relation between diet, chewing and digestion in Yakushima macaques.
Recommended citation: He, T., Honda, T., Kurihara, Y., & Thiery, G. (2020). Variation in chewing efficiency of Yakushima Japanese macaque (Macaca fuscata yakui). American Journal of Physical Anthropology, 171(1), 110-119. https://doi.org/10.1002/ajpa.23955
Published in American Journal of Primatology, 2021
Fecal particle size provides important information on the feeding and digestion of herbivores. Understanding the effects of the potential proximate determinants on fecal particle size helps us interpret this widely used measurement. In folivores, previous studies found that diet composition, dietary toughness, and age-sex-related factors, such as body size and tooth wear, influenced fecal particle size. However, the role of these factors remains unknown in frugivorous and omnivorous primates. This study aims to clarify how age-sex class and diet influence fecal particle size in omnivorous Japanese macaques in Yakushima. We expected that their variable diet and differences among age-sex classes would cause variations in fecal particle size. We simultaneously documented Japanese macaques' diet, dietary toughness, and fecal particle size in the lowland area of Yakushima in the period from March 2018 to April 2019. Unexpectedly, fecal particle size showed limited differences across months and no difference among age-sex classes. Dietary toughness showed no effects on fecal particle size, while the consumption of fruits showed only a margi
Recommended citation: He, T., Lee, W., & Hanya, G. (2021). Effects of diet and age-sex class on the fecal particle size of wild Japanese macaques (Macaca fuscata yakui). American Journal of Primatology, 83(5), e23245. https://doi.org/10.1002/ajp.23245