Mammal Study

This study reviewed worldwide spatial patterns in the food habits of Asiatic black bears (ABB) in relation to geographical (altitude, latitude, and longitude) and environmental (climate type, rainfall, temperature, and vegetation type) variables. Data on the ABB diet were collected from 29 cases based on fecal analysis. Three seasonal data were separately analyzed using principal component analysis and linear regression models. During spring, green vegetation and hard mast were mainly characterized by high loadings; latitude had a significant relationship. During summer, green vegetation, soft mast, and invertebrates were mainly characterized by high loadings; altitude, latitude, longitude, precipitation, and temperature had significant relationships. During autumn, soft and hard masts were mainly characterized by high loadings; temperature and latitude had significant relationships. Spatial variation in the bear diet was the main result of vegetation types due to climatic factors that affect the nutritional and energetic requirements of bears and the availability of local food. In contrast, the tradeoff between food availability, nutritional conditions, and energetic requirements determined the food items. However, there were many distributions where dietary information was lacking, so accumulating information is essential to elucidate the ABB feeding strategy and how it adapts to each environment.

Published online 26 June, 2025; Print publication 31 July, 2025

Leopards exhibit adaptability and thrive in human-dominant landscapes by incorporating livestock into their diet. The present study was conducted to assess the prey availability and selection patterns of leopards (Panthera pardus fusca) in two urban landscapes i.e., Indore and Jabalpur, in India. The research aimed to understand the prey population dynamics and evaluate the impact of human activities on leopard behaviour. This study employed transect surveys to estimate prey density and biomass, scat analysis to identify consumed prey species, and analysis of the secondary data from Forest Department local administration for livestock depredation incidents. Prey selection was evaluated using the Jacobs' selectivity index. Results revealed diverse prey preferences, with chital (Axis axis) and domestic dogs (Canis familiaris) being prominent diet components in both study areas. Livestock, particularly cattle, constituted a significant portion of available biomass. This study identified human-leopard negative interaction zones within the study areas prone to conflict. These findings emphasize the need for effective management strategies to mitigate human-leopard negative interactions and promote coexistence. The study contributes valuable insights into the dietary habits and prey dynamics of leopards in urban landscapes, which are crucial for their conservation and management initiatives.

Published online 19 March, 2025; Print publication 31 July, 2025

Daily torpor in small mammals can be triggered by a shortening of day length (spontaneous daily torpor), or by a reduced energy budget due to factors such as food deprivation (fasting-induced daily torpor). While some hamsters are known to enter torpor, and spontaneous daily torpor has been observed in the genus Cricetulus, it has been thought that the Chinese hamster (C. griseus) does not express torpor. In this study, we attempted to induce daily torpor in the Chinese hamster through food deprivation. We used 18 hamsters, dividing them into three groups (50% feeding, 25% feeding, and 0% feeding [fasting]), and conducted three trials of 24-h restricted feeding, with intervals for recovery. The results showed three torpor bouts within the trials: once in the 50% feeding group and twice in the 25% feeding group, but no bouts were observed in the fasting group. The mean daily minimum body temperature (Tb) decreased progressively across trials, with the lowest values being recorded during the third trial in all groups. This study reveals for the first time that fasting-induced daily torpor occurs in the genus Cricetulus, suggesting that species in this genus could use spontaneous and fasting-induced torpor mechanisms.

Published online 19 March, 2025; Print publication 31 July, 2025

Camelidae and Hippopotamidae (Artiodactyla) and Rhinocerotidae and Tapiridae (Perissodactyla) are unguligrades with pads, which support their body weight with their hooves and volar pads on their feet. In order to investigate the evolution of unguligrady from a functional morphological point of view, it is necessary to examine the limbs of living unguligrades with pads. In this study, we focused on the extremities of limbs of camelids and rhinoceroses and analyzed the differences between them and those of bovids, which are unguligrade without pads, using CT to simulate three-dimensional movements. The results showed that metapodials and proximal phalanges were interlocked by pulleys in unguligrades, whereas a large gap was observed between metapodials and proximal phalanges in unguligrades with pads. However, the angle changes of proximal phalanges of unguligrades with pads were smaller than those observed in unguligrades. This suggests that the pads inhibit wide spreading of the digits in these taxa. Whereas unguligrades, such as bovids, have adapted to various terrains by modifying the mobility of their digits, our results suggest that volar pads have limited the ability of unguligrades with pads to adapt to a variety of terrains.

Published online 19 March, 2025; Print publication 31 July, 2025

Invasive mammalian predators are the most damaging alien animal species in terms of biodiversity, particularly in island fauna. Currently, four mammalian carnivores (raccoon dogs, feral cats, American mink, and masked palm civets) have been introduced to Okushiri Island, Hokkaido, northern Japan; however, basic information for invasive species management such as their distribution and activity patterns on the Island are still unclear. This study aimed to reveal the distribution, habitat selection, and diel activity patterns of alien carnivores on Okushiri Island. Camera trapping was conducted at 31 sites from June to November 2022. We evaluated the diel activity patterns using the kernel density method and habitat selection using a generalized linear mixed model. During the 2094 camera days, we obtained the occurrence frequencies of 4105 raccoon dogs, 208 masked palm civets, 71 feral cats, and 69 American mink. The raccoon dog was active at night and day and avoided streams. The masked palm civet was only active at night, preferred grasslands, and avoided residential areas. The American mink was active at night and day and preferred streams. The feral cat exhibited crepuscular patterns and preferred residential areas. Our study revealed that raccoon dogs have a high population density on Okushiri Island.

Published online 23 April, 2025; Print publication 31 July, 2025

We used dynamic occupancy modeling and scat analysis to understand the habitat use and feeding habits of leopards in a forest-agricultural mosaic adjacent to Rajaji Tiger Reserve. The top model indicated that leopards were not detected at sites with elephants but were detected where large prey was present. Initial occupancy was higher at sites with moderate proportion of forest cover. Colonization probability decreased with increasing road density. Extinction probability was inversely correlated with distance from settlements and positively correlated with road density. Wild prey dominated the diet (69.4%), especially nilgai and sambar, whereas the contribution of domestic animals was lower (30.6%). In essence, the habitats near the settlements were more widely used in the pre-monsoon peak due to denser cover, which declined successively in latter seasonal peaks probably due to reduction in cover provided by sugarcane crops which were harvested later. Leopards favoured wild prey, which were likely supplemented with domestic prey near the settlements and roads. The conservation efforts here should prioritize the habitats and prey within the agricultural landscape to sustain leopard and prey populations in order to mitigate any conflict at manageable levels.

Published online 23 April, 2025; Print publication 31 July, 2025

The book “Animal History of Japan” published in 1944 emphasized that “marine mammal study, especially on remains, has not yet begun.” At that time, there were not enough baleen whale remains. More remains were discovered from the 1960s. Since 2017, we have worked on baleen whale fauna reconstruction in the Holocene and Pleistocene of Osaka, Japan. We hereby summarize the reported Holocene baleen whales from Japan and report the finding of two additional baleen whale remains. In total, 13 Holocene baleen whale remains with morphological descriptions have been reported from Japan, with half of them being from Osaka. Comparison between the modern stranding records and baleen whale remains from Osaka indicates that the abundance of Balaenoptera physalus is a common phenomenon. However, the remains of Eubalaena sp. represents the differences between the past and the modern records, suggesting that the population of the right whale was larger during pre-historic times.

Published online 23 April, 2025; Print publication 31 July, 2025

Understanding the food habits of wild animals is crucial for the effective management of wildlife. We investigated the diet of the Cape hare in the Djebel Messaâd mountain, northern Algeria, from September 2021 to August 2022. A total of 120 samples of faecal pellets (ten samples each month, 15–20 pellets per sample) were collected and analysed by means of 30 microhistological analysis. Over the year, the Cape hare consumed a total of 30 plant taxa from 11 families. Average monthly diet comprised mainly of Poaceae (grasses) with a relative abundance of 69.02%, Fabaceae (18.58%), Cupressaceae (6.27%), and eight other families with less than 3% of each. Besides the dominant grasses, forbs were the second most abundant botanical group (20.96%), followed by shrubs and trees, which were consumed in lower proportions (10.02%). Overall, Cape hare's diet was stable from spring to winter, with no significant differences observed both in terms of species richness and diversity. In our study area, the Cape hare can be regarded as a grazer species. Proper management measures should be taken to maintain habitat diversity and prevent its degradation such as overgrazing by livestock, which can reduce the availability of grass species for Cape hare populations.

Published online 23 April, 2025; Print publication 31 July, 2025

Invasive cat predation on island-breeding seabirds is a well-known example of impacts reducing insular biodiversity. The affected islands show drastic seasonal changes in primary prey for cats (i.e., seabirds), yet no studies have detected the timing of cats' dietary shift to seabirds. Using camera trapping, opportunistic information gathering, and fecal analysis of cats captured during the transition season between the wintering and breeding seasons of the streaked shearwaters on Mikura-shima Island, we found that cats began unexpectedly preying on the shearwaters in the middle winter when the shearwaters ever reported to stay in the wintering waters, which was also earlier than the period shown by any other monitoring records in this study. We updated our estimate to 330 shearwaters annually killed by an average cat on the island. Though the cat population is yet unknown, at least 34 980 shearwaters will be killed annually, assuming the results of our recent cat trapping as the minimum population. In addition, three landbird species—Izu thrush, Japanese wood pigeon, and Japanese scops-owl—were detected in the cat feces. Mikura-shima Island lacks management by the relevant governments to solve the cat issue. Urgent action is needed from these administrations.

Published online 23 April, 2025; Print publication 31 July, 2025

想定外に早くかつ急激な野生化ネコの海鳥への食性シフト：御蔵島に おけるオオミズナギドリの繁殖シーズン移行期に捕獲されたネコの糞分析からのエビデンス．島で繁 殖する海鳥へのネコの捕食は，島の生物多様性を低下させるインパクトに関するよく知られた例である．こ れらの島では，ネコの主要な食物（つまり海鳥）の数に季節による急激な変動があるが，これまで海鳥への ネコの食性シフトのタイミングを明らかにする研究はなかった．本研究では，御蔵島においてオオミズナギ ドリの越冬期から繁殖期への移行時期に，カメラトラップ調査，情報収集，および捕獲したネコの糞分析を 行った．その結果，ネコによるオオミズナギドリの捕食は，想定外にもこれまでの報告で越冬海域にいる時 期とされていた真冬から始まっており，また本研究のほかのどのモニタリング記録よりも早かった．この結 果を受けて，御蔵島におけるネコ1頭あたりのオオミズナギドリの年間捕殺数の推定値を330羽に更新した． 現在のところ御蔵島のネコの個体数は不明であり，したがって捕殺されるオオミズナギドリの総数も不明で あるが，近年の我々のネコの捕獲結果を最低限の個体数と仮定すると，最低でも年間34 980羽のオオミズ ナギドリがネコによって捕殺されていることになる．他にも本研究では，3種の陸鳥－アカコッコ，カラス バト，オオコノハズク－がネコの糞から検出された．現在，御蔵島においては，関係行政によるネコ問題の 解決を見据えた対策は実施されていない．関係行政による速やかな対策の実施が切望される

The recognition of a proboscidean subspecies, Mammuthus armeniacus taiwanicus, from the Pleistocene represents one of the milestones for paleontological research in Taiwan in the 1970s. However, the whereabouts of the holotype and referred specimens remain unknown due to curation issues. Here, we report the rediscovery of the holotype and five referred specimens in the Tainan City Zuojhen Fossil Park collection and National Taiwan University, out of 16 original specimens in the private and museum collections, after our intense search for historical fossil materials. Given the size difference between the holotype (smaller) from Taiwan and other Eurasian mammoths, this Taiwan mammoth may represent an island dwarf rather than only a subspecies of steppe mammoths as originally identified in 1975. Our rediscovery of original materials of mammoths from the Pleistocene of Taiwan promises to further test this taxonomic and evolutionary hypothesis in the eastern margin of Eurasia, and to elucidate the Pleistocene extinctions and faunal turnover leading to the modern biodiversity.

Published online 23 April, 2025; Print publication 31 July, 2025