Mammal Research最新文献

The threatened fishing cat (Prionailurus viverrinus) is an elusive and medium-sized cat that is adapted to mangroves, swamps, wetlands and riverine habitats. A close look at the literature indicates that fishing cats are piscivorous; however, this is based on very few studies. Understanding the patterns of resource utilisation by species is crucial for assessing their role in ecosystems and in ensuring their conservation. Therefore, our study presents insights into fishing cat feeding patterns from mangroves of the Godavari delta, Andhra Pradesh, India. We collected 303 putative fishing cat scats and conducted diet analysis using 120 genetically identified scats. Our analysis revealed that fish was the most important prey for fishing cats in the study area (61.6% in frequency of occurrence), followed by crabs (30%) and rodents (28.3%). The prey composition did not vary significantly between the three seasons but there were differences between the survey years. The niche breadth also varied across the three seasons, with lowest niche breadth estimated in summers (0.36) with highest contribution of fish in the diet and highest in winters (0.75) probably due to increased contribution of other prey items along with fish. Our results suggest that long-term conservation and survival of the fishing cats depends on fish populations, which are the main prey of the species and thus recommend the need to protect the fish populations in the Godavari delta and the surrounding riverine habitats. Given the importance of fish to the diet of the fishing cat, the health of waterways throughout their distribution must be one of the focal strategies of conservation action.

I reviewed the history of knowledge on large hairy armadillo Chaetophractus villosus in Patagonia and its current presence in Tierra del Fuego Island, a southernmost geographic region in South America shared by Argentina and Chile. My aim was to highlight what is known of this recent invasion, to identify knowledge advances and gaps, and to propose some new avenues of inquiry. This review reveals that studies on large hairy armadillo have covered the following topics: (a) introduction, spread, current distribution, and the role of physical and/or ecological barriers; (b) genetic profiling, which is ongoing and highly promising research for determining founding effects and genetic bottlenecks in an expanding alien population; (c) life history—including habitat, food, and time use, reproduction, behavior, and population dynamics; (d) interactions with sympatric consumer species—be them as mutualists or competitors—and with food plants and arthropod prey; (e) interactions with predators; (f) interactions with humans—including hunting, commercialization, facilitation, and interference; (g) an eyesore is the lack of an ecosystem approach to this invading species, because the large hairy armadillo may be deemed an ecosystem engineer, which profoundly alters its habitat and prey base and has close ties to human endeavors.

The Virginia opossum (Didelphis virginiana) has a rapidly expanding distribution in North America, but many aspects of its ecology remain relatively understudied, particularly in rural areas of its core range. We collected GPS telemetry data from 93 opossums in a rural, non-agricultural landscape in South Carolina, USA (2018–2019) to examine factors influencing space use and resource selection. Estimated male home ranges (99% utilization distributions) were on average 50% larger than those of females (mean home range 115.9 ± 103.7 ha vs 76.7 ± 75.0 ha). The home range size decreased on average by 20% with each 20% increase in deciduous land cover but was not affected by season or other landscape factors. Core area sizes (65% utilization distributions) were not influenced by sex (mean core area size 29.1 ± 23.7 ha and 22.4 ha ± 13.8 for males and females, respectively) or season, but the core area size decreased by 14% with each 400 m increase in distance from a permanent water source. Resource selection by opossums primarily occurred at the landscape level. Both males and females generally selected for wetlands while avoiding pine forests and developed/open areas, likely the result of differences in resource availability and predation risk between habitats. Opossums also tended to select for linear features such as unpaved roads and edge habitat, which may facilitate movement across the landscape. The home ranges we documented are among the largest recorded for opossums in the USA, likely the result of the relatively low resource abundance throughout our study area due to comparatively minimal anthropogenic influence.

Conservation is particularly challenging for species that are highly sensitive to disturbance and negatively affected by monitoring procedures. Australia’s ecologically and culturally significant ghost bat (Macroderma gigas) has suffered substantial population declines, in part due to disturbance and loss of roost sites. This sensitivity poses impediments to studies of the ghost bat’s ecology and behaviour, which in turn inhibits evidence-based conservation and management of the species. We used full-spectrum acoustic playback, in combination with thermal video recordings and netting, as a novel method to investigate the behavioural ecology of this enigmatic bat. We tested whether ghost bats are responsive to conspecific social vocalisations and, if so, whether responses differ according to signaller and receiver characteristics. Individuals were attracted strongly to two of four vocalisation types, and responses depended on sex, thus providing the first experimental evidence that the ghost bat’s complex vocal repertoire has multiple functions. Responses did not differ with geographic location, indicating that our method can be used across the species’ range. We discuss how full-spectrum acoustic playback helps improve our knowledge of the behavioural ecology of this species and highlight the applicability of our methods for targeting specific conservation needs in bats.

Cats, introduced on thousands of islands worldwide, are one of the greatest threats to native wildlife. An analysis of 301 scats was performed in order to study the diet of cats in a National Park in the alpine ecosystem of an oceanic island (Tenerife, Canary Islands). The results were compared with those obtained 35 years ago. In this study, eight types of vertebrates were detected in the cat diet: two endemic reptiles, four introduced mammals, and two birds. Although introduced rabbits were the most important prey, accounting for 53.9% of the biomass in the diet, this figure is among the lowest recorded in the Canary Islands. Data show a shift from the diet 35 years ago, with a decrease in the percentage of rabbits consumed, from 73% of diet biomass in 1986 to 53.9% today, and an increase mainly not only in reptiles but also in native birds. This change is due to a decrease in the rabbit population, probably motivated by the incidence of haemorrhagic disease (RHDV2). Using a daily intake of 170 g, we estimated that a single cat could prey on 1331 vertebrates/year. Assuming a low cat density of 1 cat/km², the total cat population in the National Park would kill 257,739 vertebrates, being native species particularly vulnerable to predation, with 166,249 reptiles and 5588 birds annually. Thus, with the aim of updating and improving management strategies for the conservation of native biodiversity, there is a need for new research on invasive predators on islands where diet may change over time.

Passive acoustic monitoring has emerged as a scalable, noninvasive tool for monitoring many acoustically active animals. Bioacoustics has long been employed to study wolves and coyotes, but the process of extracting relevant signals (e.g., territorial vocalizations) from large audio datasets remains a substantial limitation. The BirdNET algorithm is a machine learning tool originally designed to identify birds by sound, but it was recently expanded to include gray wolves (Canis lupus) and coyotes (C. latrans). We used BirdNET to analyze 10,500 h of passively recorded audio from the northern Sierra Nevada, USA, in which both species are known to occur. For wolves, real-world precision was low, but recall was high; careful post-processing of results may be necessary for an efficient workflow. For coyotes, recall and precision were high. BirdNET enabled us to identify wolves, coyotes, and apparent intra- and interspecific acoustic interactions. Because BirdNET is freely available and requires no computer science expertise to use, it may facilitate the application of passive acoustic surveys to the research and management of wolves and coyotes, two species with continental distributions that are frequently involved in high-profile and sometimes contention management decisions.

The White-lipped Peccary (WLP) is a large-sized mammal that lives in groups and needs large, preserved areas to survive. Over the last decades, the distribution area of the WLP has been reduced, being absent from areas where its occurrence is expected, such as the central region of southwestern Goiás, Brazilian Midwest. Therefore, here we presented eight new records of WLP in southwestern of Goiás state, with information on group size and landscape context. WLPs were recorded by camera trap, and we extracted the percentage of native cover (NC%), mean of Euclidean nearest-neighbor distance (MENND), and largest native patch area (LP (hectares)) in the landscape occupied by them. The WLP group size ranged from 1 to 52 individuals in anthropized landscapes (4.6 to 30.7 of NC%), with a MENND range of 89.4 to 165 m and LP ranged from 48.8 to 297.9. These findings could be an indication that the species is returning to use the region. However, we stress that this area may not support viable WLP populations in the long-term due to the level of anthropization of the studied landscape.

Vehicle collisions with wild pigs (Sus scrofa) are reported almost everywhere this species is found. However, this is one of the least studied and characterized forms of damage that these invasive animals cause in the United States (U.S.). We analyzed 518 wild pig-vehicle collisions (WPVCs) that took place statewide in Georgia between 2015 and 2021. From that dataset, we analyzed several parameters in order to better understand and characterize these accidents on a scale that had previously not been done in the U.S. Wild pig-vehicle collisions were reported from 105 out of the 159 counties in Georgia, increasing in number annually over the seven-year period. WPVCs were most likely to occur in the fall (37%). A duration weighted time of day analysis showed that WPVCs were most frequent at dusk. Most (97%) reported accidents were caused by live wild pigs, with the remainder being due to collisions with already dead or road-killed pigs. Most (86%) collisions involved a single wild pig while the remainder occurred with two or more pigs. Collisions occurred mostly with passenger cars on dry, straight, and level two-lane blacktop roads under dark, unlighted conditions. Nine percent of the vehicle accidents involving wild pigs resulted in injuries to the drivers and passengers. Some of the most severe injuries reported were caused by swerving to avoid striking wild pigs. No human fatalities were recorded due to these accidents. Wild pig-vehicle collisions are costly and dangerous and should be closely monitored and mitigated by the agencies responsible for motorist safety, transportation infrastructure, and wildlife management.