Journal of Mammalogy最新文献

This study presents the first systematic revision of kangaroo mice, the heteromyid genus Microdipodops, in over 8 decades. The study relies on a suite of genetic (karyology and nuclear and mitochondrial DNA sequencing) and phenetic (cranial morphometrics and pelage colorimetry) characters to examine differentiation within the genus. We also present the first molecular phylogeny of the subfamily Dipodomyinae (includes kangaroo mice and kangaroo rats, Dipodomys) that incorporates all currently recognized species. Building on previous studies (including unpublished materials) and incorporating additional laboratory analyses and fieldwork, we find genetic evidence to recognize 6 species of Microdipodops organized into 2 subgenera as follows: M. Microdipodops, including M. (M.) albiventer, M. (M.) megacephalus, M. (M.) oregonus, and M. (M.) polionotus; and M. Psammophilomys, new subgenus, which includes M. (P.) pallidus and M. (P.) ruficollaris. All 6 species are endemic to the Great Basin Desert of western North America. We are unable to discriminate among these species using discriminate function analyses of cranial and pelage morphometric characters; indeed, the species are morphologically cryptic but genetically distinctive. We find strong molecular phylogenetic support for both a monophyletic Microdipodops and Dipodomys. Molecular divergence-time analyses show that the 2 subgenera of Microdipodops diverged from each other about 4.8 million years ago (Ma) and that the 3 sister-species pairs diverged approximately 1.2, 1.4 and 1.9 Ma, which compares to sister species of Dipodomys that diverged between 0.8 and 3.8 Ma in the same analysis. Expanded fieldwork, specimen collecting, and genetic sampling show range extensions and a reorganized distributional patterning of species of Microdipodops across the Great Basin Desert. Most noteworthy among the distributional changes is our discovery that kangaroo mice of the Owyhee Desert (ecoregion includes southwestern Idaho, southeastern Oregon and north-central Nevada), previously deemed a relictual isolate, all belong to the same species and that this species should bear the name M. (M.) megacephalus given that the type specimen of the genus (from Halleck, in northern Nevada) is genetically most closely related to other kangaroo mice of the Owyhee Desert. The ecological preferences of M. (M.) megacephalus appear to be strikingly dissimilar to those of its congeners. With the descriptions of 4 new species, and revised taxonomic concepts for 2 others, this study has important implications for the conservation and management of kangaroo mice across their distribution.

A mainland native nocturnal arboreal glider Petaurus notatus (Krefft's Glider) was introduced to Tasmania in the 1830s as a pet and its subsequent escape and landscape spread has been associated with the predation of endemic and migratory birds. Using geometric morphometrics, we assessed whether P. notatus experienced a phenotypic response, visible in their skull, after introduction to Tasmania. We found significant skull form variation between Tasmanian (n = 57) and Victorian (n = 102) glider specimens. Specifically, there is an increase in rostrum length-particularly at the mid-cranium-a dorsal shift of the frontal bones, and increase in posterior angle of the coronoid process on the mandible. Whether this morphological change is associated with a dietary shift towards carnivory or because of multiple ecological pressures is unclear. However, similar morphological variations identified in the Tasmanian specimens have previously been linked to an increase in carnivory in other species as noted by other researchers.

Despite mammals constituting fewer than 0.3% of all described species, their conservation is compelling for a number of reasons. They contribute to biodiversity and are important in maintaining and regulating ecological communities. Many mammals have significant cultural and economic value, serving as sources of food, medicine, and tourism revenue. Furthermore, the conservation of mammals often leads to the protection of entire habitats, benefiting numerous other species and preserving ecosystem services that are critical for human well--being. Humans share a unique evolutionary history with other mammal species, making their preservation important for scientific research, education, and understanding of our own biology and evolution. In spite of this, mammalian biodiversity is at severe risk, with 26% of all mammal species threatened with extinction. Here, we propose to use a 4-step framework with which to approach conservation strategy for mammalian biodiversity. The framework is structured and based on a protocol initially established from the standpoint of parasites by Daniel R. Brooks and collaborators in 2014. The 4 key phases are documentation (species discovery and specimen collection); assessment (species relationships, genetic diversity, and climate change vulnerability); monitoring (tracking populations and habitats over time); and action (addressing the taxonomic impediment-the lack of human and financial resources to undertake taxonomy, as well as the discrepancy between real number of existing species and human knowledge of biodiversity-and expanding protected areas). The successful integration of politics, politicians, and stakeholders into the process of conservation is critical to the success of the protocol because of the requirement to enact policy. And the urgency is now, because nothing is more vital to the human condition than preservation of biodiversity.

Adaptation of mammals to seasonally changing environments is crucial for survival and fitness. Some mammals migrate or alter their behavior when resources are limited, while others hibernate-a strategy that offers profound seasonal metabolic savings. During hibernation, both body temperature and metabolic rate are reduced, minimizing energy expenditures. However, when hibernacula temperatures decrease to below their body temperature setpoint, mammals must increase thermoregulatory output to maintain body temperature. Thus, the thermal characteristics of hibernacula play a crucial role in determining overwinter metabolic expenditure. We identified hibernacula locations of the endangered New Mexico Jumping Mouse (Zapus luteus), described physical characteristics of the hibernacula, and compared soil temperatures between hibernacula and randomly selected sites. Additionally, we explored the relationship between ambient air and soil temperatures at hibernacula to understand their influence on thermal buffering and the stability of microclimatic conditions. In Arizona and Colorado from 2019 to 2021, we tracked New Mexico jumping mice into hibernation to confirm hibernacula locations. We used radiotelemetry and Passive Integrated Transponder tags with a priori criteria to identify underground locations. We confirmed and characterized hibernacula for 4 females and 7 males (n = 11). Soil temperatures at 3 depths (-10, -30, and -50 cm) were measured near each hibernaculum and compared to random sites. Hibernacula depth averaged 29 ± 2 cm (range 21 to 45 cm). Soil temperatures at hibernacula were colder and warmed later in spring compared to random sites. Female hibernacula were colder ( $\overline{x}$ = 2.1 ± 0.03 °C) than those of males ( $\overline{x}$ = 2.5 ± 0.02 °C). Hibernacula were mostly north-facing, possessed vegetation cover, and located on average 59.6 ± 19.6 m from perennial water. The consistent selection of hibernacula with physical traits that maintain colder, more stable temperatures emphasizes the importance of conserving microclimatic conditions critical for the recovery of this species, especially amid environmental change.

Climate change is a driver of species extirpation, particularly for local endemics. The niche reduction hypothesis provides a conceptual framework to understand how the realized niche of a declining species is reduced from its historical niche to its contemporary niche due to threats. The Organ Mountains Colorado Chipmunk (Neotamias quadrivittatus australis) is an example of an endemic montane mammal for which climate change may be a threat. We used occupancy models developed for historical sites to evaluate the extent of extirpations and their causes. We used occupancy models developed for random sites to evaluate the contemporary distribution and realized niche. Our results suggest that the Organ Mountains Colorado Chipmunk has undergone broadscale extirpation (extirpated from 64% of sites) with a lower elevation range boundary contraction of 262 m in the past 30 yr. Chipmunks were extirpated from hotter and more arid biotic communities and persisted in drainages that provide cooler and more mesic conditions. Chipmunks avoided conifer forest, which were an integral part of their historical niche, suggesting that the Organ Mountains Colorado Chipmunk may have undergone a reduction in its realized niche. The Organ Mountains Colorado Chipmunk has become a de facto "functional habitat specialist" restricted to climate change refugia, further increasing its vulnerability to climate change and other threats.

Understanding animal activity budgets is essential for assessing habitat use and ecological roles, with important implications for conservation. Despite their ecological significance, the behavior of Common Hippopotamus (Hippopotamus amphibius) remains poorly studied, particularly at night. This study aimed to (i) quantify the 24-h activity budget of hippos; (ii) evaluate how behavior changed over the day and varied seasonally; (iii) examine how behavior varied between different areas; and (iv) between age classes. This study presents the first 24-h observational activity budget of hippos and the first behavioral data from Botswana. Hippo behavior varied significantly by time of day, season, study area, and age class. Hippos exhibited a well-defined circadian rhythm, with activity peaking and dipping at sunrise, sunset, around midday, and midnight. Contrary to the persistent assumption that hippos rest in water by day and graze on land all night, hippos in this study fed during only a quarter of the night and were active for a similar proportion of the day. Hippos often spent hours of the day on land feeding or basking in the sun, challenging the idea that they rely heavily on water to prevent their skin from cracking. Resting and feeding behaviors varied with fluctuating water levels, with aquatic vegetation playing a more significant role in their diet than previously assumed. These findings provide valuable insights into hippo ecology and can help predict how they may respond to environmental changes, particularly in regions experiencing increasing human pressures.

The Common Fallow Deer (Dama dama; hereafter "fallow deer") has been widely translocated from its native Mediterranean range and is now present on all continents except Antarctica. In some countries-such as Australia-introduced populations of fallow deer have increased in range and abundance, negatively affecting agricultural production. However, little is known about how this species uses these agricultural landscapes annually, seasonally, or daily. We used GPS collars to track the hourly movements of 68 adult fallow deer (25 males, 43 females) at 3 sites in mixed pastoral farmland (a mosaic of open eucalypt woodland and pasture) in eastern Australia between 2020 and 2024. We estimated annual and monthly home ranges, daily distance moved, and diel movement cycles. As expected, annual home ranges (using the biased random bridge method) were larger for males (median = 1,848.1 ha, 95% CrI: 929.2 to 3,584.0 ha) than females (median = 646.3 ha, 95% CrI: 368.1 to 1,068.5 ha), and home ranges and core areas were similar across the 3 sites. Both sexes had a strong crepuscular movement pattern that was consistent across sites. Male fallow deer increased their movement rates in April-May (i.e., during the mating season), and their movement patterns were most restricted during summer. Female fallow deer movements were more consistent across the year than those of males, but movement patterns were also most restricted during summer. There was substantial individual variation in daily movement patterns between and within sites, especially during the mating season. Most individuals exhibited strong site fidelity, but some males and females made short excursions (up to a week and 10 km) from their home range. The strong site fidelity of fallow deer suggests that management strategies utilizing repeated culling will be most effective at reducing overabundant fallow deer populations in Australian agricultural landscapes.

Collagen-elastin (CE) bundle patterns in the wing membrane have been used to identify individual bats; however, this method has not been widely adopted, likely owing to the laborious nature of manually comparing wing images through visual inspection. We tested the effectiveness of using an accessible, feature-based, pattern-recognition software-HotSpotter-to identify individuals using patterns of CE bundles in the bat wing. We collected photos from 24 adult (n = 192 photos) big brown bats (Eptesicus fuscus) and their direct offspring (n = 34 pups; n = 136 photos) by illuminating the ventral surface of the wing with ultraviolet light. Upon running a query match comparison on a selected reference image, HotSpotter ranks every other photo in the database based on an assigned similarity score. We found that HotSpotter correctly presented the top-ranked image as another image of the same individual at higher-than-chance performance. The software also performed better than chance when considering matches to images with the same age (adult/juvenile), sex (male/female), wing side (left/right), and known-relatedness (mother-offspring or twin) to the bat in the queried image. The proportion of correct matches increased with the number of top-ranked images included in the initial query. These results are encouraging because they suggest that pattern-recognition software has the potential to automate recognition of bats based on CE bundle patterns in photos of bat wings. With further refinements in the technology, we think it may be possible to achieve nearly 100% accuracy of individual identification.

Natural history collections are repositories of biodiversity specimens that provide critical infrastructure for studies of mammals. Over the past 3 decades, digitization of collections has opened up the temporal and spatial properties of specimens, stimulating new data sharing, use, and training across the biodiversity sciences. These digital records are the cornerstones of an "extended specimen network," in which the diverse data derived from specimens become digital, linked, and openly accessible for science and policy. However, still missing from most digital occurrences of mammals are their morphological, reproductive, and life-history traits. Unlocking this information will advance mammalogy, establish richer faunal baselines in an era of rapid environmental change, and contextualize other types of specimen-derived information toward new knowledge and discovery. Here, we present the Ranges Digitization Network (Ranges), a community effort to digitize specimen-level traits from all terrestrial mammals of western North America, append them to digital records, publish them openly in community repositories, and make them interoperable with complimentary data streams. Ranges is a consortium of 23 institutions with an initial focus on non-marine mammal species (both native and introduced) occurring in western Canada, the western United States, and Mexico. The project will establish trait data standards and informatics workflows that can be extended to other regions, taxa, and traits. Reconnecting mammalogists, museum professionals, and researchers for a new era of collections digitization will catalyze advances in mammalogy and create a community-curated trait resource for training and engagement with global conservation initiatives.