Mammal Study

We examined the habitat use of the Indo-Pacific bottlenose dolphin Tursiops aduncus around Amakusa-Shimoshima Island, Japan. Of the approximately 200 individuals that resided in the waters north of this island, about 30 individuals moved to the south around Nagashima Strait, with different environments, and then disappeared. The habitat use of these dolphins in the south was examined using land- and boat-based surveys and compared with that in the north. The ferry crew sightings were also analyzed. Intensively used areas, which were estimated using a first-passage time analysis, were shallow waters close to the shore, located around small islands or in coastal areas facing the strait. Resting behavior, characterized by low apparent moving speed and synchronous dives, was observed in the intensively used areas. The dolphins tended to be on the south side of the strait in daytime hours, and the similar trend was observed at low and ebb tides. The habitat use, such as having certain resting places, possible habitat areas at night, and tidal-affected distribution was similar to that in the north. Resting places were scattered and not stable throughout the study period. The disappearance of dolphins may be due to drop in suitability of resting places.

Published online 22 April, 2024; Print publication 31 July, 2024

Rodents serve as the main carriers for leptospirosis disease. Home range and habitat usage are part of the ecological study, which was less explored in disease ecology. In this study, Rattus norvegicus (RN), Rattus rattus complex (RR), and Sundamys muelleri (SM) were chosen due to their high prevalence with pathogenic Leptospira. Three pairs of each species were tracked from urban, semi-urban, and forested areas. The rats were fitted with a transmitter radio-collar and tracked with a portable telemetry receiver consisting of a 3-element Yagi antenna and located using standard methods of ground-based triangulation. Home range and core area were higher in the forest species (SM) than urban species (RN and RR). RN roaming and nesting areas were restricted inside houses and sewers, which is similar to RR roaming outside houses but nesting in houses. SM shows more expansive roaming areas in the forest but occasionally visits dump sites. Food resources, primarily from leftovers and dumping sites, were found to be the main factor in the viability of these species. The information on the movement ecology of rats could give accurate and valuable data on the population control, by targeting the specific areas occupied by the rats.

Published online 14 May, 2024; Print publication 31 July, 2024

Penggunaan kawasan keliaran dan makrohabitat oleh tikus perumah takungan utama Leptospira di Selangor, Malaysia. Tikus adalah pembawa utama penyakit leptospirosis. Kawasan keliaran dan penggunaan habitat adalah sebahagian daripada kajian ekologi yang kurang dieksplorasi dalam ekologi penyakit. Dalam kajian ini, Rattus norvegicus (RN), Rattus rattus complex (RR), dan Sundamys muelleri (SM) dipilih disebabkan prevalen tinggi mereka dengan Leptospira patogenik. Tiga pasang dari setiap spesies dijejaki dari kawasan bandar, pinggiran bandar, dan hutan. Tikus-tikus ini dipasangkan dengan kolar-radio pemancar dan dijejaki dengan penerima telemetri mudah alih yang terdiri daripada antena Yagi 3-elemen dan dikesan menggunakan kaedah triangulasi atas tanah yang standard. Kawasan keliaran dan kawasan teras adalah lebih besar untuk spesies hutan (SM) berbanding dengan spesies bandar (RN dan RR). Kawasan merayau dan bersarang RN adalah terhad di dalam rumah dan sistem pembentungan, hampir sama dengan RR yang merayau di luar rumah tetapi bersarang di dalam rumah. SM menunjukkan kawasan merayau yang lebih luas di hutan, tetapi kadang-kadang melawat tapak pelupusan sampah. Sumber makanan, terutamanya dari sisa-sisa makanan dan tapak pelupusan sampah, didapati menjadi faktor utama dalam keupayaan spesies ini untuk terus hidup. Maklumat mengenai ekologi pergerakan tikus boleh memberikan data yang tepat dan bernilai mengenai kawalan populasi, iaitu dengan menumpukan kepada kawasan-kawasan tertentu yang didiami oleh tikus.

Assamese macaques (Macaca assamensis) and rhesus macaques (M. mulatta) are sympatrically distributed in Nepal but differ in many traits. Data on 11 groups of Assamese macaques and 13 groups of rhesus macaques in northwestern Kathmandu show that Assamese macaques inhabited only protected forests in Shivapuri Nagarjun National Park, whereas rhesus macaques inhabited even small forests disturbed by people in temples close to cultivated and urban areas, frequently raided crops, and were provisioned. Assamese macaques inhabited higher altitude and formed smaller groups with more adult males and fewer immatures than rhesus macaques. Rhesus macaques' proclivity to be provisioned supported their large groups. However, their strict dominance hierarchy might make low-ranking males solitary, whereas many males of Assamese macaques might be able to stay together because of their affiliative relationship with other males. In Nepal, Assamese macaques might adopt more K-reproductive strategies with a larger body, fewer offspring, and lower twin frequency in stable circumstances, compared to rhesus macaques. Competition for resources promotes niche separation in food choice and habitat use, which might strengthen the inter-species difference and make their coexistence possible. We recommend careful maintenance of forests to protect Assamese macaques, and effective managements of provisioned and crop-raiding rhesus macaques.

Published online 2 May, 2024; Print publication 31 July, 2024

ネパールのカトマンズ北西部におけるアッサムモンキー（Macaca assamensis）とアカゲザル（M. mulatta）の分布と群れの構成． ネパールではアッサムモンキー（Macaca assamensis）とアカゲザル（M. mulatta）が同所的に生息しているが，両者の特徴は多くの点で異なる。カトマンズ北西部のアッサムモンキー11群とアカゲザル13群のデータによると，アッサムモンキーはShivapuri Nagarjun国立公園内の攪乱されていない保護森にのみ生息していたのに対し，アカゲザルは耕作地や街に近い寺院の攪乱された小さな森にも生息し，よく農作物を荒らしたり，餌付けされたりしていた。アカゲザルよりもアッサムモンキーは標高の高い所に生息し，小さな群れを形成し，群れ内のオトナオスと未成熟個体の割合は低かった。アカゲザルの大きな群れは餌付けされやすいという彼らの特徴がもたらしたものだ。しかしアカゲザルでは厳しい優劣関係によって低順位オスはハナレオス（群れに属さず単独で暮らすオス）となっていた。それに対してアッサムモンキーの多くのオスは他のオスと親和的関係を築くことで群れ内に留まれているようだ。 またネパールではアカゲザルと比べてアッサムモンキーは大きな体で子孫と双子をあまり作らずに安定した環境で暮らすK繁殖戦略をとっていたのかもしれない。資源を巡る競合が食物選択と生息地利用のニッチ分割を促進し，それが種間の相違を強めて，両種の共存を可能にしているらしい。アッサムモンキーを保護するために注意深く森を維持する一方，農作物被害を起こしたり餌付けされたりしているアカゲザルに対しては効果的な管理が必要である。

Conservation of large mammals inhabiting steep and rugged terrain in high elevations presents unique challenges for collection of demographic and ecological information to serve the conservation efforts. Studies that utilize capturing of wildlife provide valuable information on the biology of the species, including otherwise inaccessible information on the relation of the species with its habitat. However, capturing wildlife also presents unique challenges in terms of effort and budget allocation and animal welfare. In this study, capturing of nine individuals of the near threatened (NT) wild goat (Capra aegagrus) was done using two methods: clover trap and drop net. These methods were compared by evaluating the strengths and weaknesses of each method. According to the results of the study, clover trap method prevailed, when animal welfare, field effort, ease of capture area selection, budget, and technological constraints were taken into account. On the other hand, drop net method was found as the better alternative, considering multiple captures and ease of habituation to trap site. The findings of this study offer valuable insights to guide researchers and to prepare them for challenges that they may encounter in their studies involving capturing of large herbivores such as wild goat.

Published online 20 May, 2024; Print publication 31 July, 2024

The raccoon (Procyon lotor) is an invasive species in Japan and has been identified as a susceptible host and reservoir of tick-borne diseases. In our study conducted on the Miura Peninsula, Kanagawa Prefecture, Japan, a total of 47 604 ticks were collected from 253 raccoon carcasses (92.3% of raccoons). The predominant tick species found was Haemaphysalis flava, constituting 97.4% of the collected ticks, followed by eight other species from three genera. Generalized linear mixed models with raccoon sex, age, season, and land use at the captured site as explanatory variables indicated that raccoon sex and seasonal variations were significant factors influencing tick infestations across all stages and sexes of H. flava. Raccoon age indicated an impact on adult and larval H. flava. Additionally, the land use was relevant only for the model of nymph, with urban areas being a significant factor. Our analysis suggests that male raccoons have a substantial role for increasing and spreading ticks. We also noted a significant concentration of ticks infesting ears and head of raccoons. These findings contribute to the development of efficient and quantitative evaluation methods for tick infestation towards disease prevention strategies in wildlife management.

Published online 6 June, 2024; Print publication 31 July, 2024

三浦半島のアライグマ（Procyon lotor）の季節，性，齢，体表部位によるマダニ寄生状況の違い．日本国内において外来種アライグマ（Procyon lotor）は，マダニ媒介感染症病原体の感受性宿主，またはレゼルボア（感染巣）であることが確認されている．神奈川県三浦半島で実施した調査では，253 頭のアライグマの死骸（アライグマの 92.3%）から 47 604 頭のマダニが採集された．マダニはHaemaphysalis flava が 97.4% と最も多く，次いで他の 3 属 8 種が採取された．アライグマの性，齢，季節，捕獲場所の土地利用状況を説明変数とした一般化線形混合モデルにより，H. flava の全ステージおよび性別において，アライグマの性別と季節がマダニの咬着数に影響を及ぼす有意な要因であることが示された．また，アライグマの齢は H. flava の成ダニと幼ダニに影響を与えることが示された．さらに，土地利用区分はメス成ダニに関連し，都市部が有意な要因であった．分析の結果，オスのアライグマは，マダニの増加と拡散に大きな役割を担っていることが明らかになった．また，アライグマの耳介と顔部にマダニが集中して咬着していることも明らかになった．これらの知見は，野生動物管理による感染症予防対策に向けて，マダニの咬着状況を効率的かつ定量的に評価する手法において有用な知見となることが期待される．

An individual of baleen whale remains from a Holocene sediment in Osaka, Japan was examined in 1976. It was identified as “a fin or blue whale”. Here, the specimen is described and identified as a fin whale based on the cranium, periotic, and newly added mandibular condyle features. In posterior view, the mandibular condyles of blue whales are wider than other rorquals. The mandibular condyle is structurally massive and frequently preserved, and taxonomically informative element that can be used to distinguish fin whales from blue whales. The fin whale remains emphasized that fossil specimens as well as modern strandings of fin whale are few around the Seto Inland Sea. However, the numbers are relatively high near the entrances of the Seto Inland Sea, such as Osaka Bay. More reports of well preserved specimens allowing species identification from Holocene sediments are required to reconstruct the history of whales from the past to present.

Published online 20 May, 2024; Print publication 31 July, 2024

Motivated by food, long-tailed macaques (Macaca fascicularis) in the Universiti Kebangsaan Malaysia (UKM) campus, have been observed exploiting waste, damaging bins, and scattering rubbish, resulting in unpleasant odours, unsightly surroundings, increased risk of disease outbreaks and community nuisance. This study aims to examine macaques' waste exploitation behaviour patterns during foraging and their relationship with incidence of nuisance at UKM. Scan sampling was conducted between April 2022 and February 2023, comparing anti-animal bins with four other bin types. Waste exploitation and nuisance behaviour data were analysed using one-way analysis of variance (ANOVA), Tukey's HSD test, and Pearson correlation. Waste exploitation, particularly removing rubbish away, was the most common behaviour (37.7%), and trespassing in the college was the most frequent nuisance behaviour (90.8%). The smallest bin exhibited the highest frequency of waste exploitation (41.8%) and nuisance behaviour (45.9%). The use of anti-animal bins reduced waste exploitation behaviour by 99.3% and nuisance to humans by 81.4%. A negative correlation (r = –0.755, n = 23013, P < 0.001) was found between macaque waste exploitation and nuisance behaviour, suggesting that the amount of human-generated refuse influences macaque food resource selection. These findings will inform the management of both M. fascicularis and waste at UKM.

Published online 19 June, 2024; Print publication 31 July, 2024

Wild boars in Asia heavily depend on bamboo shoots, a high-protein springtime food source, although the timing of shoot emergence varies by bamboo species, and some species have a limited availability window. This study observed wild boar feeding behavior on three major Japanese bamboo species to elucidate their specific patterns. The number of feeding signs increased in the order of Phyllostachys edulis, P. nigra var. henonis, and P. bambusoides, according to the shoot emergence phenology of each species. A common feature in the three species was that the cumulative relative frequency of feeding signs exceeded 50% before the temperature reached the thermosensitive limit temperature of each species, which is a suitable criterion for shoot emergence. Bamboo shoots that survived feeding by wild boars accounted for only 3% of most of the bamboo shoots produced in a year. Moreover, annual differences were detected in the feeding risk by wild boars of P. nigra var. henonis and P. bambusoides. Abandoned bamboo forest areas continue to increase in size and provide food resources for wild boars. This study indicates the importance of understanding bamboo forests at the species level and proper management of these forests.

Published online 19 June, 2024; Print publication 31 July, 2024

Captive condition sometimes evokes behaviors that are not observed in animals in the wild. A confirmation of the behaviors in the wild is needed to exclude the possibility of captivity-specific behaviors. Narrow-ridged finless porpoises are reported to produce two sound types for communication: “packet sound”, which is a series of pulses with repeated pulse packets (a sound series consisting of a few pulses with irregular, short inter-pulse intervals), and “burst pulses”, which are a pulse train with significantly shorter inter-pulse intervals compared to packet sound. Burst pulses were reported from wild narrow-ridged finless porpoises of Seto Inland Sea–Hibiki Nada population in Japan, while the packet sound was only recorded in captive conditions. Here, we report the packet sound as well as burst pulses from wild narrow-ridged finless porpoises of Ise–Mikawa Bays population in Japan. We found six packet sounds and six burst pulses out of 5 h recording of a self-contained underwater sound recorder, at a frequency of 0.020 times/min for each sound type. It is suggested that packet sound is produced by not only captive but wild narrow-ridged finless porpoises. Future studies should focus on the behavioral state when producing communication sounds.

Published online 22 April, 2024; Print publication 31 July, 2024

Phylogeography of terrestrial mammals on islands is complicated because of the geological changes in the island configuration or their past population dynamics on the nearby landmass. To understand the function of Shodoshima Island in the Seto Inland Sea in preserving lineages of Japanese macaques (Macaca fuscata) and sika deer (Cervus nippon), we investigated the molecular phylogeny of these species on the island. We analyzed a partial sequence of the mitochondrial DNA (mtDNA) control region of the two species. We identified four mtDNA haplotypes in macaques, including western and eastern Japan lineages. Two mtDNA haplotypes for deer were discovered, which were categorized into only the northern Japan lineage. Their nucleotide sequences were identical except for a tandem repeat. These results suggest that the phylogeographic trend was remarkably different between the two species, which may be due to the migration of multiple lineages of macaques to the island when it was connected to Honshu Island, and a bottleneck effect on the deer population caused by overhunting. Some haplotypes were probably unique to the Shodoshima population of both species. The presence of region-specific haplotypes suggests the importance of Shodoshima Island to maintain genetic diversity of the species.