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Management of ungulate populations to the desired density and/or demographic composition are challenged by contrasting aims of different stakeholders. For example, hunters may want to maximize hunting opportunities whereas commercial forest owners may want to minimize moose densities to mitigate browsing damage. In addition, the return of large predators such as wolves Canis lupus affects the possible harvest yield of ungulates and influences the population composition through their selection of specific age classes. The aim of this study was to gain a better understanding of factors related to the variation in moose Alces alces harvest. We used moose harvest statistics from the period 2012–2020, wolf annual monitoring data, annual brown bear Ursus arctos density, proportion of young forest per management unit, and proportion of agricultural land per management unit (index for productivity and roe deer Capreolus capreolus density) to explain variation in moose harvest across different management units at two spatial levels in two bordering countries, Sweden and Norway. The results showed variable responses in total harvest to changes in wolf territory density both at the regional and local management level. The proportion of young forest was correlated with both increased total harvest and proportion of calves. Increased proportion of agricultural land was linked to both increased total harvest and proportion of calves, likely due to that increased roe deer densities re‐directed wolf predation from moose to roe deer, and an inverse relationship with brown bear density. Differences between countries may be due to differences in the management regime of moose, both in an historical and present perspective. Improved monitoring for individual hunting areas over time will be important for both the understanding of how different ungulate populations are affected by various factors and for the desired management of wildlife populations shared across borders. [ABSTRACT FROM AUTHOR]

Survival of juvenile ungulates represents an important demographic parameter that influences population dynamics within ecosystems. In many ecological systems, the mortality of juvenile ungulates is influenced by various factors, including predation by large carnivores, human hunting activities and weather. While wolves Canis lupus are known to prey on moose Alces alces throughout all seasons, brown bears Ursus arctos primarily engage in predation during early summer, while human harvest primarily occurs in autumn and early winter. Hence, understanding the impacts of predation, harvest, and weather on the survival of juvenile moose is crucial for adaptive population management and the determination of sustainable harvest rates. To investigate the summer and autumn–winter survival of moose calves in relation to carnivore occurrence (wolf presence and bear density), summer habitat productivity, winter severity, human harvest, and migratory behaviour (migratory versus resident), we analysed data collected from 39 GPS‐collared female moose in south‐central Scandinavia. Our findings revealed significant interannual variation in summer survival rates, with areas with relatively higher bear densities exhibiting calf mortality rates twice as high as those in regions with low bear density. During the autumn–winter period, calf survival was lowest in the presence of wolves and deep snow, and it exhibited a negative correlation with the proportion of clearcuts and young forests within the mother's home range. Additionally, calf survival was negatively correlated with the risk of human hunting, and calves of stationary females displayed ten times higher survival rates compared to migratory individuals. Our study provides valuable insights into the survival of moose calves coexisting with two large carnivores and humans. Improving our understanding of the mechanisms causing calf survival to fluctuate has become increasingly important as many local moose populations in Scandinavia are declining and exposed to expanding predator populations, intense hunting pressure, and other threats associated with climate change. [ABSTRACT FROM AUTHOR]

The article discusses the emergence of icing-related injuries in polar bears at high latitudes due to climate change, specifically the formation of ice on body parts, hair loss, and skin ulcerations. The study conducted in Kane Basin and East Greenland between 2012 and 2022 observed these injuries primarily affecting adult bears, with severe cases showing blocks of ice up to 30 cm in diameter adhered to foot pads. Indigenous subsistence hunters in Greenland and Nunavut were interviewed to gather information on the frequency and potential causes of these injuries. The study highlights the ecological implications of these injuries on polar bear populations and emphasizes the need for further research to understand and mitigate these impacts. [Extracted from the article]

The multiobjective (MO) optimizers show great promise in solving constrained engineering structural problems. This paper introduces a MO version of the Brown Bear Optimization (BBO) algorithm, inspired by the foraging behavior of brown bears. The proposed Multiobjective Brown Bear Optimization (MOBBO) algorithm is applied to five structural optimization problems, including 10‐bar, 25‐bar, 60‐bar, 72‐bar, and 942‐bar trusses, aiming to minimize both mass and maximum nodal deflection simultaneously. Comparative evaluations against six benchmark algorithms demonstrate MOBBO's superior convergence, solution diversity, and effectiveness in addressing highly constrained problems. The hypervolume (HV) and inverted generational distance (IGD) metrics place MOBBO in first rank according to the Friedman test, with an average standard deviation of 0.0002. Moreover, the spacing‐to‐extent (STE) and generational distance (GD) metrics rank MOBBO second. The final Friedman rank test highlights MOBBO's overall dominance, achieving a first rank. Best Pareto plots, diversity graphs, and box plot analyses further suggest MOBBO's superior performance and convergence compared to existing algorithms. Therefore, the MOBBO algorithm can be effectively applied to various MO optimization tasks in industry, offering refined global optimization solutions and contributing valuable insights to the field of MO algorithms. [ABSTRACT FROM AUTHOR]

The article "Mammal coloration as a social signal—the debate is still open: a comment on Howell and Caro (2024)" published in the Journal of Zoology discusses the importance of mammalian visual communication through color patches within sociosexual contexts. The study by Howell and Caro analyzed 2726 extant terrestrial mammals to explore relationships between coloration and socioecological factors. While the study suggests limited use of conspicuous color patches for sociosexual signaling, recent research on bears indicates the significance of fur marks in social communication. The article concludes by questioning why certain taxa use vision in addition to olfaction for communication, emphasizing the need for further exploration in understanding mammal communication. [Extracted from the article]

Interspecific interactions among species of the same guild play a critical role in shaping their realized niches, and their understanding may disclose mechanisms of coexistence. Investigating interactions among apex predators is of ecological and management interest, especially in human‐dominated landscapes where type and intensity of their interspecific competition may be affected by human interference. During 2005–2010, we investigated, by means of GPS‐telemetry, interactions between brown bears (n = 19) and wolves (n = 7) in a long‐established national park in the central Apennines, Italy, where bears and wolves have always coexisted close to humans. Based on a K‐select analysis and a randomization approach, we assessed the extent of overlap between the species' niches on a seasonal basis. Bears and wolves clearly segregated in fall but not during summer when overlap between their realized niches suggests a convergent adaptation to a seasonal peak of anthropogenic pressure. However, using multi‐species resource selection functions (RSFs) at the home range level (i.e., third‐order selection), we revealed that habitat selection by bears and wolves was reciprocally affected also when their niches overlapped, possibly disclosing mechanisms of fine‐scale resource partitioning. In early summer, bears selected areas with a high probability of resource selection by wolves, but in late summer avoided areas positively selected by wolves. On the contrary, wolves avoided areas where the probability of resource selection by bears was high, both in late summer and fall. These results indicate that bears and wolves do interact in our study area and, although the actual behavioral mechanisms are unknown, they reciprocally and asymmetrically affect their realized niche and habitat selection patterns. Further research is needed to better understand how anthropogenic factors impact intraguild interactions and what are the effects at the population and community levels. [ABSTRACT FROM AUTHOR]

Animal sociality, the extent and manner in which conspecifics associate with each other, ultimately affects an individual's survival and reproductive success. It is shaped by the spatiotemporal configuration and composition of the social units (e.g. individual, pair, group) in a population. Here, we assessed the formation and structure of social networks of a presumed nonsocial species with individual-based movement data of 153 GPS-marked brown bears, Ursus arctos. We explored changes in the frequency of dyadic associations in relation to distinct seasonal patterns (i.e. mating, hyperphagia and hunting seasons) that affect bear behaviour. We found seasonally distinctive frequencies in brown bear associations throughout their active period and that reproduction was the main driver for associations in the population, that is, the highest frequency of associations occurred during the mating season and male–female dyads during the mating season included the majority (73%) of observed associations. We also observed dyadic associations during the hyperphagia and hunting seasons, but found no significant changes in frequency during these seasons. In addition, we found that social structures during both the mating and nonmating periods were nonrandom, that is, dyadic associations occurred more often than expected. Animal sociality is commonly viewed as a classification of social versus nonsocial, but our results suggest that it is rather a dynamic continuum primarily influenced by variation in a species' spatiotemporal configuration (i.e. seasonal movements, social unit structure) and demographic composition (i.e. age, sex). Our results also support the contention that studies focusing on animal sociality should include a sociospatial perspective, as both components are tightly linked. Since sociality can affect individual fitness, and vice versa, advancing the knowledge on assumed 'solitary' species is paramount for the conservation and sustainable management of their populations. • Animal sociality is a dynamic continuum instead of a binary classification. • The sociospatial environment of a population is under constant change. • We performed a network analysis using a GPS location database from a solitary species. • In brown bears, a 'solitary species', sociality is driven by reproduction. • Brown bear social interactions are nonrandom outside the mating season. [ABSTRACT FROM AUTHOR]

In North America, polar bears (Ursus maritimus), grizzly bears (U. arctos), and American black bears (U. americanus) occasionally injure or kill humans. Although bear-inflicted human injuries are uncommon, they generate media attention that can lead to fear and unreasonable perceptions of the risk of bear attacks. Information on the behavioral responses of grizzly and black bears during interactions with people can provide a factual basis regarding the risks associated with recreating in bear habitats and assist land managers in developing and prioritizing bear safety messages. To address those objectives, we collected 17,171 reports of grizzly and black bear reaction behavior during interactions with people in Yellowstone National Park, USA, between 1991 and 2022. We used Bayesian Multinomial Logistic Regression models to examine the odds of attack, agitation and/or warning, flight, or curious behavioral reactions versus neutral responses in bear–human interactions. We found that reaction behavior depended on both the species involved and the location of the interaction. In developed areas and along roadsides, neutral responses were most likely for both species. On front-country trails, odds of curious or flee reactions were greater than neutral responses for both species. The odds of agitation and/or warning reactions from grizzlies were also greater in this setting. In backcountry campsites, there were marginally higher odds of black bears attacking; whereas, grizzlies had marginally higher odds of attacking during off-trail backcountry interactions. Although bear attacks were uncommon in all locations, grizzlies were ∼3.9× more likely than black bears to injure people in backcountry areas. Bear interactions with people were generally predictable; grizzly and black bears exhibited neutral behaviors or fled during most interactions. Curious approaches, agitation and/or warning behaviors, physical contact, and attacks were uncommon. Safety messages encouraging calm, confident responses during bear–human interactions are warranted, and may have better efficacy than those that generate fear and apprehension. [ABSTRACT FROM AUTHOR]

Prey must balance resource acquisition with predator avoidance for survival and reproduction. To reduce risk of predation, prey may avoid areas with high predator use, but if they are unable to due to resource acquisition requirements, they may instead change their habitat use or movement speed to mitigate predation risk. Prey risk response may depend on spatially or temporally varying forage availability as well as seasonal variation in prey vulnerability and availability of alternate foods for predators. To quantify how prey respond to spatial and temporal variation in risk of brown bear predation, we examined Roosevelt elk (Cervus canadensis roosevelti) spatiotemporal behavior responses to brown bear (Ursus arctos) habitat use on Afognak and Raspberry islands, Alaska, using Global Positioning System location data during elk parturition (20 May–15 June), summer (16 June–20 September), and autumn (21 September–10 November). During parturition and summer, elk used forest and shrub landcover in areas of higher brown bear probability of use. During parturition, elk used areas with lower forage productivity in areas of higher bear probability of use, and movement speed decreased with higher bear probability of use, especially in shrub landcover. During summer, elk used areas with higher forage productivity in areas of higher brown bear probability of use. During autumn, elk were less likely to use areas with higher bear habitat probability of use across landcover categories and forage productivity. During summer and autumn, elk movement speed increased with higher brown bear probability of use. Elk behavioral response to risk of brown bear predation could increase energy expenditure and decrease their ability to acquire forage, therefore negatively impacting survival and reproduction with spatiotemporal variation in risk response potentially amplifying these impacts. [ABSTRACT FROM AUTHOR]

The polar bear (Ursus maritimus) occupies a relatively narrow ecological niche, with many traits adapted for cold temperatures, movement across snow, ice and open water, and for consuming highly lipid-dense prey species. The divergence of polar bears from brown bears (Ursus arctos) and their adaptation to their Arctic lifestyle is a well-known example of rapid evolution. Previous research investigating whole genomes uncovered twelve key genes that are highly differentiated between polar and brown bears, show signatures of selection in the polar bear lineage, and are associated with polar bear adaptation to the Arctic environment. Further research suggested fixed derived alleles in these genes arose from selection on both standing variation and de novo mutations in the evolution of polar bears. Here, we reevaluate these findings based on a larger and geographically more representative dataset of 119 polar bears and 135 brown bears, and assess the timing of derived allele fixation in polar bears by incorporating the genomes of two Late Pleistocene individuals (aged 130–100,000 years old and 100–70,000 years old). In contrast with previous results, we found no evidence of derived alleles fixed in present-day polar bears within the key genes arising from de novo mutation. Most derived alleles fixed in present-day polar bears were also fixed in the Late Pleistocene polar bears, suggesting selection occurred prior to 70,000 years ago. However, some derived alleles fixed in present-day polar bears were not fixed in the two Late Pleistocene polar bears, including at sites within APOB, LYST, and TTN. These three genes are associated with cardiovascular function, metabolism, and pigmentation, suggesting selection may have acted on different loci at different times. [ABSTRACT FROM AUTHOR]

ABSTRACT Through killing and instilling fear in their prey, large terrestrial carnivores shape the structure and function of ecosystems globally. Most large carnivore species have experienced severe range and population declines due to human activities, and many are now threatened with extinction. Consequently, the impacts of these predators on food webs have been diminished or lost completely from many ecosystems. Kill rates provide a fundamental metric for understanding large carnivore ecology and assessing and comparing predation within and across ecological communities. Our systematic review of large terrestrial mammalian carnivore kill rates reveals significant positive geographic (North America, Europe, and Africa) and taxonomic (grey wolf Canis lupus, puma Puma concolor, lion Panthera leo, and Eurasian lynx Lynx lynx) bias, with most studies apparently motivated by human–carnivore conflict over access to ungulate prey and wildlife management objectives. Our current understanding of the behaviour and functional roles of many large carnivore species and populations thus remains limited. By synthesising and comparing kill rates, we show that solitary carnivores (e.g. brown bears Ursus arctos and most felids) exhibit higher per capita kill rates than social carnivores. However, ungulate predation by bears is typically limited to predation of neonates during a short period. Lower per capita kill rates by social carnivores suggests group living significantly reduces energetic demands, or, alternatively, that group‐living carnivores defend and consume a greater proportion of large prey carcasses, or may acquire more food through other means (e.g. scavenging, kleptoparasitism) than solitary hunters. Kill and consumption rates for Canidae – measured as kilograms of prey per kilogram of carnivore per day – are positively correlated with body mass, consistent with increasing energy costs associated with a cursorial hunting strategy. By contrast, ambush predators such as felids show an opposite trend, and thus the potential energetic advantage of an ambush hunting strategy for carnivores as body mass increases. Additionally, ungulate kill rates remain relatively constant across solitary felid body sizes, indicative of energetic constraints and optimal foraging. Kill rate estimates also reveal potential insights into trophic structuring within carnivore guilds, with subordinate carnivores often killing more than their larger counterparts, which may be indicative of having to cope with food losses to scavengers and dominant competitors. Subordinate carnivores may thus serve an important role in provisioning food to other trophic levels within their respective ecosystems. Importantly, kill rates also clarify misconceptions around the predatory behaviour of carnivores (e.g. spotted hyaenas Crocuta crocuta and wolverines Gulo gulo are often considered scavengers rather than the capable hunters that they are) and thus the potential impacts of various carnivore species on their ecological communities. Despite the importance of kill rates in understanding predator–prey interactions, their utility is not widely recognised, and insufficient research limits our ability to fully appreciate and predict the consequences of modified predation regimes, justify current management actions affecting carnivores, or inform effective conservation measures. Together with other important research on predator–prey interactions, robust kill rate studies that address the research deficiencies we highlight will provide a deeper understanding of the foraging behaviours and potential ecosystem impacts of many of the world's carnivores, thus aiding effective conservation and management actions. [ABSTRACT FROM AUTHOR]

Hyperdontia refers to an excess number of teeth past the expected number of teeth for an individual located in the mandible or maxilla. These extra teeth are often referred to as "supernumerary." This condition is a relatively uncommon, infrequent phenomenon scarcely documented in Ursidae globally, with only a handful of examples documented in literature. In 2008, an indigenous hunter harvested a grizzly bear (Ursus arctos) in Smithers, British Columbia, Canada. The bear exhibited 7 maxillary incisors, with a supernumerary tooth present. This observation serves as the first-ever record of the supernumerary dentition of the incisors in brown bears. [ABSTRACT FROM AUTHOR]

Many conservation actions must be implemented with limited data. This is especially true when planning recovery efforts for extirpated populations, such as grizzly bears (Ursus arctos) within the Bitterroot Ecosystem (BE), where strategies for reestablishing a resident population are being evaluated. Here, we applied individual-based movement models developed for a nearby grizzly bear population to predict habitat use in and near the BE, under scenarios of natural recolonization, reintroduction, and a combination. All simulations predicted that habitat use by grizzly bears would be higher in the northern half of the study area. Under the natural recolonization scenario, use was concentrated in Montana, but became more uniform across the northern BE in Idaho over time. Use was more concentrated in east-central Idaho under the reintroduction scenario. Assuming that natural recolonization continues even if bears are reintroduced, use remained widespread across the northern half of the BE and surrounding areas. Predicted habitat maps for the natural recolonization scenario aligned well with outlier and GPS collar data available for grizzly bears in the study area, with Spearman rank correlations of ≥0.93 and mean class values of ≥9.1 (where class 10 was the highest relative predicted use; each class 1–10 represented 10% of the landscape). In total, 52.4% of outlier locations and 79% of GPS collar locations were in class 10 in our predicted habitat maps for natural recolonization. Simulated grizzly bears selected habitats over a much larger landscape than the BE itself under all scenarios, including multiple-use and private lands, similar to existing populations that have expanded beyond recovery zones. This highlights the importance of recognizing and planning for the role of private lands in recovery efforts, including understanding resources needed to prevent and respond to human-grizzly bear conflict and maintain public acceptance of grizzly bears over a large landscape. [ABSTRACT FROM AUTHOR]

Fertility control has traditionally been applied in zoos to control captive populations, and reversible contraception is important. However, contraceptive methods for male bears have not been reported. We aimed to establish a reversible contraceptive for male brown bears by investigating the effects of a gonadotropin‐releasing hormone (GnRH) vaccine (Improvac®) that was developed for the immune castration of pigs. We vaccinated six bears with two sequential doses of 400 (n = 2) or 600 μg Improvac® (n = 4) with a 1‐month interval during the pre‐breeding season (February to April). We compared the reproductive parameters (testosterone levels and semen parameters) of the six vaccinated and four non‐vaccinated (control) bears once during the breeding season (May or June). To investigate whether the reproductive performance could be restored in the following year of contraception, we also compared the reproductive parameters once during the breeding season in two bears between the year with GnRH vaccination and the following year without vaccination. Vaccination treatments suppressed reproductive parameters in 5 bears, although vaccination with 400 μg of Improvac® was not effective in one bear. Testosterone levels and the rate of progressive sperm motility were significantly lower, and total sperm count and testis size tended to be lower in vaccinated bears, compared with the controls. Blood biochemical findings and direct observations after Improvac® vaccination did not reveal side effects. Moreover, testosterone levels and spermatogenic scores of two bears were restored in the following year. We confirmed that the Improvac® vaccine elicited a reversible contraceptive effect in male brown bears. [ABSTRACT FROM AUTHOR]

During the reproductive period, mating strategies are a significant driver of adaptations in animal behaviour. For instance, for polygamous species, greater movement rates during the mating season may be advantageous due to the increased probability of encountering several potential mates. The brown bear Ursus arctos is a solitary carnivore that lives at low densities, with a polygamous mating system and an extended mating season of nearly 3 months. Here, we hypothesized that male brown bears may show changes in movement patterns and space‐use behaviour during their mating season. Using long‐term (2002–2013) telemetry data from the Finnish Karelia male population (n = 24 individuals; n = 10 688 GPS locations), we first analysed daily movement metrics, that is, speed, net and total distance with respect to the period (mating vs. post‐mating) and several environmental predictors. Then, we conducted a step‐selection analysis for each of these periods. Throughout the year, male bears selected forested/shrub habitats and increased movement rates near main roads. During the mating season, reproductive needs seem to trigger roaming behaviour in adult males to maximize encounter rates with potential receptive females. However, all movement metrics increased within areas of high human activity, suggesting a bear response to a higher risk perception while using those areas. During the post‐mating period, overlapping with the bear hyperphagia and the hunting season, males selected anthropogenic areas farther from main roads and trails, suggesting a trade‐off between foraging opportunities and risk avoidance. [ABSTRACT FROM AUTHOR]

Simple Summary: This study explored the differences in skull and mandible shapes between male and female brown bears using advanced 3D imaging techniques. The main goal was to understand how and why these shapes vary, focusing on whether these differences are due to size or sex. The research found that male brown bears have longer and thinner skulls, with notable changes in specific areas like the back of the head and jaw muscles. These differences are likely linked to the larger body size of male bears, which may require stronger muscles and a different skull structure to support their greater weight and chewing needs. The study highlights the importance of these shape variations for the bears' adaptation to their environment. Understanding these differences can help conserve and manage brown bear populations by providing insights into their physical development and needs. This knowledge is valuable for wildlife biologists, conservationists, and anyone interested in the natural world, offering a clearer picture of how animals adapt over time. The present study aimed to describe the skull and mandibles of the brown bear (U. arctos) from the Dancing Bear Belitsa Park using advanced 3D morpho-geometric techniques. The objective was to explore how sexual dimorphism and size influence cranial structures using advanced 3D geometric morphometric methods. Three-dimensional models of the skulls and mandibles of 12 brown bears were used. Differences in skull morphology between male and female brown bears were observed in this study. The male brown bear skull, larger than the female, exhibited a more pronounced extension of the upper part of the nuchal region towards the posterior. Additionally, the posterior part of the frontal region appeared notably thinner in male brown bears compared to females. Analysis of the mandible revealed that the masseteric fossa was more developed in males than females. These shape differences between males and females were found to be influenced by body size. Statistical analyses indicated a significant allometric effect of body size on skull PC1 values, suggesting that giant bears tend to have more elongated skulls. This implies a relationship in which larger individuals exhibit greater cranial elongation. In contrast, mandible PC1 values showed no size-related variation, indicating that mandibular shape is less influenced by overall body size. However, PC2 values in the mandible increased significantly with larger specimens, indicating a larger masseteric fossa in larger bears. This morphological adaptation potentially enhances feeding efficiency and bite strength in larger individuals, reflecting functional adaptations in brown-bear mandibular morphology. These findings contribute to our understanding of sexual dimorphism and size-related morphological adaptations in brown bears, providing insights into their adaptation biology and ecological roles within their habitats. [ABSTRACT FROM AUTHOR]

Abstract Following glacial retreat after the last ice age, brown bears (Ursus arctos) recolonised Scandinavia. Previous research based on mitochondrial markers suggests that bears recolonised from both the north and the south, with a contact zone in central Scandinavia. More recently, the Scandinavian brown bear was subjected to a strong population decline with only ca. 130 remaining individuals, due to intense human persecution approximately 100 years ago. Here, we analyse 41 ancient, historical, and modern mitochondrial genomes, to examine the number of female lineages involved in the postglacial recolonisation event and temporal changes in the Scandinavian brown bears’ mitochondrial genetic diversity. Our results support the bi-directional recolonisation hypothesis, indicating multiple mitochondrial lineages from clade 1a possibly followed a southern route, while only a single lineage from clade 3a appears to have followed a northern route. Furthermore, we found that the recent bottleneck had a strong impact on the southern subpopulation, resulting in only one remaining haplotype in the contemporary brown bears. For the northern subpopulation, the impact was moderate, and most haplotypes were retained throughout the bottleneck. By exploring the postglacial recolonisation and recent population pressures, our study enhances understanding of how these factors have influenced the genetic diversity of Scandinavian brown bears.

For the first time in the Ukrainian Polissia and the Chornobyl Radiation and Ecological Biosphere Reserve (ChREBR), a concentrated linear distribution of bear-marked spruce trees was found at the abandoned estates of the village of Opachychi along the second terrace of the Prypiat River floodplain. Individual sightings of bears (Ursus arctos) in the Ukrainian Polissia have been known since the 1990s, but there are no reliable data on the reproduction of this species. The abundance of bears in Belarus has increased in recent years, which leads to the possibility of females coming to the Polissia from the north. Dried spruce trees without resin were not marked by the bear, and the animal moved on to live trees. Friction and more intensive marking of trees was recorded mainly in the eastern direction. Most of the marked spruce trees were upright with no branches to the height of the marking. The intensive marking behaviour of bears in 2023 in the ChREBR can be considered as the appearance of a female, as signalling to a female, and as a sign of dominance towards a male competitor. Two adult males were observed near one of the marked trees (data from amateurs). Special field surveys are needed to identify females with cubs to confirm or refute the hypothesis that the intensity of bear marking can be used in the event of the presence of a female bear in oestrus. Along the bear-marked trees in the village of Opachychi of the ChPEBR, an ecological trail and a visitor centre of large carnivores and herbivores should be created, which would be popular destinations. It is advisable to arrange a location for wildlife observations in an abandoned house for photo and video shooting, as is usually done in Sweden, Bulgaria, Romania, and Spain. In such tours, the effectiveness of the observation is not guaranteed and only preliminary statistics of wildlife encounters are provided. For this purpose, it is advisable to create two feeding areas for predatory mammals with dry food, as well as a salt marsh and a feeding trough for ungulates. The majority of the ChREBR territory has a low incidence of markings. The bear in the Polissia, as elsewhere in Europe, is expanding its range naturally, but at a slow pace due to the low intensity of female dispersal. Tree marking by bears was also observed in Chernihiv Oblast, in the Mizhrichynskyi Regional Landscape Park. It is advisable to release several bears in the ChEBR to create a reproductive centre for this species in the Polissia.

Deforestation, forests diminution, and scarcity of natural food are widely regarded as the primary factors contributing to the presence of brown bears in urban areas of Romania, and human-bear conflicts. Public misunderstanding regarding forest and bear management practices often leads to skepticism of expert information, worsened by misinformation in the media and social networks. This article aims to offer insight into deforestation and human-bear conflicts in Romania. It analyzes national and international official data, to assess the percentage of forested areas, primary causes of deforestation, brown bear population and density, and the number of human-bear conflicts. It also compares Romanian data with other European countries to explore the potential correlation between forested area percentage and human-bear conflicts. Between 2000 and 2020, Romania's forest area comprised 29.02% of its land, while Poland, France, and Italy had percentages of 29.89%, 30.04%, and 30.65%, respectively. Interestingly, the proportion of forest cover did not consistently correlate with the frequency of conflicts. Countries with similar forest percentages to Romania experienced fewer conflicts, whereas countries with higher percentages, like Slovenia (61.65%) and Slovakia (39.86%), faced numerous human-bear conflicts due to the dense brown bear population. The management of bears served as a valuable indicator of the extent of damage caused by these animals. In Croatia, Sweden, Slovakia, and Slovenia, where 10-16% of the bear population was harvested annually, lower levels of damage were reported. In contrast, Romania, with an annual harvest of only 2-3% of the bear population, experienced higher levels of damage.

Various domestic and wildlife species have been found susceptible to and infected with SARS‐CoV‐2, the causative agent of COVID‐19, around the globe, raising concerns about virus adaptation and transmission to new animal hosts. The virus circulation in the white‐tailed deer population in North America has further called to action for virus surveillance in the wildlife. Here, we report on the first SARS‐CoV‐2 survey of wild animals in Japan, where frequent wildlife invasions of urban areas have occurred due to the limited predation, field abandonment, the increase of human acclimatization. Genetic testing using nasal swabs and serological screening have been conducted for sika deer, brown bears, raccoons, and raccoon dogs captured in Hokkaido prefecture from the end of the Delta variant wave to the spread of the Omicron variant, between March 2022 and February 2023. No viral RNA was detected in raccoons (0/184), sika deer (0/107), and brown bears (0/14) indicating that the virus was unlikely to spread within the population of these animal species. Among 171 raccoons, 20 raccoon dogs, 100 sika deer, and 13 brown bears, one raccoon, one brown bear, and two deer tested positive in the antibodies screening with multispecies SARS‐CoV‐2 N‐protein ELISA. Still, ELISA‐positive samples tested negative in three other serological tests, emphasizing the importance of confirming serological screening results. Our results suggested that SARS‐CoV‐2 was unlikely to spillback from humans to wildlife in Hokkaido during the study period, with the emergence of new variants, continuous surveillance is of utmost importance. [ABSTRACT FROM AUTHOR]

Hibernation is a key adaptation for coping with unfavorable climatic conditions and low food availability in areas with severe winter conditions. While understanding the physiology and phenology of this adaptation has received considerable attention, comparatively little information is available on how hibernation will be affected by changing climate conditions. We used GPS telemetry data from 20 free‐ranging brown bears monitored over 31 winters between 2007 and 2022, to identify behavioral strategies of bears during winter. We applied behavioral change point analysis to quantify brown bears' hibernation phenology in a population close to the bear's southern latitudinal range limit in Europe where supplementary food is available to bears year‐round. We observed winter behavior patterns that varied across age and reproductive classes but also within individuals between winters. Among 31 winter events, we registered six cases in which bears exhibited a single hibernation/stationary period and 19 events where hibernation was split into up to five stationary periods. Moreover, six winter events did not show behaviors consistent with hibernation and individuals remained partly or completely active throughout winter. The movement of these active bears decreased with increasing snow depth. In addition, these winter‐active bears showed higher fidelity to supplementary feeding sites during the winter period compared to the rest of the year. Our data suggest that an abundance of human‐provided food resources during winter may facilitate the emergence of different wintering strategies in brown bears. Furthermore, supplemental feeding sites in combination with predicted mild winters and prolonged natural food availability suggest that the use of hibernation as an energy‐saving strategy to overcome severe environmental conditions may decrease in the future. [ABSTRACT FROM AUTHOR]

During 17 spring and summer field seasons between 1973 and 1999, we documented 220 bouts of nursing by dependent polar bear (Ursus maritimus Phipps, 1774) cubs at Radstock Bay, Nunavut, Canada. The overall mean duration of nursing bouts for cubs-of-the-year (COY) and yearlings (YRLG) litters was 7.1 min (standard deviation (SD) = 3.3, range = 1–23). Mean nursing bout durations of one- and two-cub litters of COY and YRLG in spring and summer seasons ranged from 6.09 to 7.78 min and from 5.00 to 9.18 min, respectively. The overall mean duration of inter-nursing intervals for COY and YRLG litters was 5.7 h (SD = 4.9, range = 0.0–35.0). The mean inter-nursing interval for one-cub litters was 6.4 h (SD = 4.6, range = 0.0–20.2) and for two-cub litters was 5.1 h (SD = 5.1, range = 0.0–35.0). We found no evidence for effects of season or cub age class on nursing behavior. We found weak evidence that two-cub litters nurse slightly longer than one-cub litters, potentially reflecting reduced nursing efficiency due to sibling rivalry. There was neither evidence for diel patterns in nursing behavior nor a detectable relationship between the cessation of nursing and the onset of hunting or sleeping by the adult female. [ABSTRACT FROM AUTHOR]

The Swedish brown bear Ursus arctos population is protected, but managed with legally defined hunting seasons. Management decisions (e.g., hunting quotas) are frequently changed and should be based on knowledge about demographic parameters, but collecting sufficient data in the field is time consuming and expensive. An efficient method to collect data on reproductive output could be counting placental scars in the uteri of female brown bears, because hunters in Sweden are required to collect samples (including reproductive organs) of harvested bears and submit them to the authorities. We assessed the reliability of placental scar counts to determine reproductive performance by counting the number of young with female radio-collared brown bears and comparing that with placental scar counts after those females had been harvested. We found that staining uteri improved the detection of placental scars. The differences between number of scars detected before and after staining the uteri, increased significantly with female age. The number of placental scars and number of observed cubs-of-the-year accompanying females corresponded well 2 and 3 years after birth; relatively small deviations between them might have occurred because of early cub mortality prior to the observations after leaving the den. Placental scar counts can provide accurate information on age of primiparity, evidence for reproductive aging (senescence), and reproductive productivity, and therefore inform decisions regarding adaptive management, sustainable hunting, and conservation. [ABSTRACT FROM AUTHOR]

In wild brown bears, likely factors triggering hibernation response to harsh environmental conditions are temperature, photoperiod, and food resources availability. In fact, constantly fed captive brown bears are described as skipping hibernation being active all year-round. Is the hibernation response so flexible and subordinate to contingencies, or else is an adaptation that, if dismissed, may negatively impact on bear well-being? This study investigates the potential hibernation response in captive brown bears under unvaried management conditions using an integrative approach simultaneously analyzing multiple animal-based variables together with environmental covariates. Data from a mid-latitude zoo revealed distinct behavioral, fecal glucocorticoids, and body condition score seasonal fluctuations, resembling natural hibernation cycles, despite constant food access. Environmental variables like photoperiod and visitor numbers significantly influenced activity levels. Bears exhibited behaviors indicative of hyperphagia and fall transition, such as appetitive feeding and denning behaviors. Hormonal analyses revealed high fecal cortisol metabolites levels during hyperphagia, suggesting physiological responses to seasonal changes. Findings underscore the importance of environmental cues and food availability in shaping zoo bear behavior and physiology. Considering that the hibernating vs. non-hibernating description might represent an oversimplification, management strategies should deal with captive bear potential need to freely express their adaptive predispositions by accommodating their natural behaviors, such as providing denning spots and adjusting diet composition as soon as typical hyperphagic and predenning behaviors emerge, ultimately enhancing their well-being. [ABSTRACT FROM AUTHOR]

The rapid evolution of GPS devices, and therefore, collection of GPS data can be used to investigate a wide variety of topics in wildlife research. The combination of remotely collected GPS data with on‐the‐ground field investigations is a powerful tool for exploring behavioral ecology. "GPS cluster studies" are aimed at pinpointing and investigating identified clusters in the field. Activity clusters can be based on various parameters (e.g., distance between GPS locations and the number of locations needed to establish a cluster), which are closely related to the set research questions. Variation in methods across years within the same study may result in data collection biases. Therefore, a streamlined method to parametrize, generate interactive maps, and extract activity cluster data using a predefined approach will limit biases, and make field work and data management straightforward for field technicians. We developed the "ClusterApp" Shiny application in the R software to facilitate a step‐by‐step guide to execute cluster analyses and data management of cluster studies on any species using GPS data. We illustrate the use of the "ClusterApp" with two location datasets constructed by data collected on brown bears (Ursus arctos) and gray wolves (Canis lupus). [ABSTRACT FROM AUTHOR]

The assessment of animal body condition has important practical and management implications for endangered wildlife populations. The nutritional condition of a population can be evaluated in a non-invasive way using photogrammetry techniques, avoiding direct manipulation. This study evaluates the utility of using body condition scoring (BCS) based on the visual assessment of subcutaneous fat and muscle from the body contour as a non-invasive method to quantify body condition in free ranging bears from camera trap photographs. Photographs of Apennine brown bears (Ursus arctos marsicanus), taken between 2007 and 2009 in the Abruzzo, Lazio and Molise National Park (PNALM, Italy), were used to evaluate the potential of this technique. BCS assessment was performed on 754 photographs representing 71 independent observations. Forty-eight of these photographs were selected to also score quantitative body ratios using a standardised measure of torso height. BCS varied seasonally, as expected by food availability and brown bear nutritional physiology, and it was also positively correlated to all three body ratios. Our findings indicate that BCS assessment is a good proxy for body condition, and that camera trap data can be effectively used to assess and monitor the nutritional condition of bear populations, such as the critically endangered one in central Italy. [ABSTRACT FROM AUTHOR]

This article, titled "Ecological Consequences of Animal Behavior Change: A Case of Brown Bear Digging for Cicada Nymphs," explores the effects of brown bear digging on soil nutrients, larch needle traits, and radial growth in the Shiretoko World Heritage site in northern Japan. The study found that brown bear digging decreased fine root biomass of larch, soil water and nitrogen availability, and needle nitrogen content, ultimately negatively affecting the radial growth of larches. The findings suggest that the ecological roles of brown bears have changed due to their behavior change in response to the creation of plantation forests. The article includes several photographs illustrating the research. [Extracted from the article]

Harvest regulations commonly attenuate the consequences of hunting on specific segments of a population. However, regulations may not protect individuals from non‐lethal effects of hunting and their consequences remain poorly understood. In this study, we compared the movement rates of Scandinavian brown bears (Ursus arctos, n = 47) across spatiotemporal variations in risk in relation to the onset of bear hunting. We tested two alternative hypotheses based on whether behavioural responses to hunting involve hiding or escaping. If bears try to reduce risk exposure by avoiding being detected by hunters, we expect individuals from all demographic groups to reduce their movement rate during the hunting season. On the other hand, if bears avoid hunters by escaping, we expect them to increase their movement rate in order to leave high‐risk areas faster. We found an increased movement rate in females accompanied by dependent offspring during the morning hours of the bear hunting season, a general decrease in movement rate in adult lone females, and no changes in males and subadult females. The increased movement rate that we observed in females with dependant offspring during the hunting season was likely an antipredator response because it only occurred in areas located closer to roads, whereas the decreased movement rate in lone females could be either part of seasonal activity patterns or be associated with an increased selection for better concealment. Our study suggests that female brown bears accompanied by offspring likely move faster in high‐risk areas to minimize risk exposure as well as the costly trade‐offs (i.e. time spent foraging vs. time spent hiding) typically associated with anti‐predator tactics that involve changes in resource selection. Our study also highlights the importance of modelling fine‐scale spatiotemporal variations in risk to adequately capture the complexity in behavioural responses caused by human activities in wildlife. [ABSTRACT FROM AUTHOR]

Humans are perceived as predators by many species and may generate landscapes of fear, influencing spatiotemporal activity of wildlife. Additionally, wildlife might seek out human activity when faced with predation risks (human shield hypothesis). We used the anthropause, a decrease in human activity resulting from the COVID‐19 pandemic, to test ecology of fear and human shield hypotheses and quantify the effects of bear‐viewing ecotourism on grizzly bear (Ursus arctos) activity. We deployed camera traps in the Khutze watershed in Kitasoo Xai'xais Territory in the absence of humans in 2020 and with experimental treatments of variable human activity when ecotourism resumed in 2021. Daily bear detection rates decreased with more people present and increased with days since people were present. Human activity was also associated with more bear detections at forested sheltered sites and less at exposed sites, likely due to the influence of habitat on bear perception of safety. The number of people negatively influenced adult male detection rates, but we found no influence on female with young detections, providing no evidence that females responded behaviorally to a human shield effect from reduced male activity. We also observed apparent trade‐offs of risk avoidance and foraging. When salmon levels were moderate to high, detected bears were more likely to be females with young than adult males on days with more people present. Should managers want to minimize human impacts on bear activity and maintain baseline age–sex class composition at ecotourism sites, multiday closures and daily occupancy limits may be effective. More broadly, this work revealed that antipredator responses can vary with intensity of risk cues, habitat structure, and forage trade‐offs and manifest as altered age–sex class composition of individuals using human‐influenced areas, highlighting that wildlife avoid people across multiple spatiotemporal scales. [ABSTRACT FROM AUTHOR]

Renewable energy sources (RES) are currently being substantially integrated into the power grid because of the recent liberalization of the energy market and associated benefits to both the environment and the economy. A significant amount of renewable energy sources are stochastic and weather dependent, being integrated into the power system that causes a mismatch between the generation of power and the load demand, which creates major issues like variations in frequency and power transmission between the regions. So it is necessary to maintain the frequency and tie-line power variations within a defined range. This is known as automatic generation control (AGC) or load frequency control (LFC). This paper uses brown bear optimization algorithm (BOA) to tune the PID and cascaded PI-PDN controllers for LFC of the renewable integrated two-area power system. The ITAE objective function is utilized to obtain optimal gains of the PID controller. The performance of LFC with BOA-tuned PID controller is compared with other optimization techniques named grey wolf optimization technique (GWO) and particle swarm optimization (PSO) on a RES integrated two-area power system under various scenarios. Further, the effectiveness of the BOA is verified by comparing performance of the PID and cascaded PI-PDN controllers. According to simulation results, BOA offers superior performance in comparison with the GWO and PSO technique. [ABSTRACT FROM AUTHOR]

Copyright of Düzce University Journal of Forestry / Düzce Üniversitesi Orman Fakültesi Ormancılık Dergisi is the property of Duzce University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Harmonising methodology between countries is crucial in transborder population monitoring. However, immediate application of alleged, established DNA-based methods across the extended area can entail drawbacks and may lead to biases. Therefore, genetic methods need to be tested across the whole area before being deployed. Around 4,500 brown bears (Ursus arctos) live in Norway, Sweden, and Finland and they are divided into the western (Scandinavian) and eastern (Karelian) population. Both populations have recovered and are connected via asymmetric migration. DNA-based population monitoring in Norway and Sweden uses the same set of genetic markers. With Finland aiming to implement monitoring, we tested the available SNP-panel developed to assess brown bears in Norway and Sweden, on tissue samples from a representative set of 93 legally harvested individuals from Finland. The aim was to test for ascertainment bias and evaluate its suitability for DNA-based transnational-monitoring covering all three countries. We compared results to the performance of microsatellite genotypes of the same individuals in Finland and against SNP-genotypes from individuals sampled in Sweden (N = 95) and Norway (N = 27). In Finland, a higher resolution for individual identification was obtained for SNPs (PI = 1.18E-27) compared to microsatellites (PI = 4.2E-11). Compared to Norway and Sweden, probability of identity of the SNP-panel was slightly higher and expected heterozygosity lower in Finland indicating ascertainment bias. Yet, our evaluation show that the available SNP-panel outperforms the microsatellite panel currently applied in Norway and Sweden. The SNP-panel represents a powerful tool that could aid improving transnational DNA-based monitoring of brown bears across these three countries. [ABSTRACT FROM AUTHOR]

Deforestation, forests diminution, and scarcity of natural food are widely regarded as the primary factors contributing to the presence of brown bears in urban areas of Romania, and human-bear conflicts. Public misunderstanding regarding forest and bear management practices often leads to skepticism of expert information, worsened by misinformation in the media and social networks. This article aims to offer insight into deforestation and human-bear conflicts in Romania. It analyzes national and international official data, to assess the percentage of forested areas, primary causes of deforestation, brown bear population and density, and the number of human-bear conflicts. It also compares Romanian data with other European countries to explore the potential correlation between forested area percentage and human-bear conflicts. Between 2000 and 2020, Romania's forest area comprised 29.02% of its land, while Poland, France, and Italy had percentages of 29.89%, 30.04%, and 30.65%, respectively. Interestingly, the proportion of forest cover did not consistently correlate with the frequency of conflicts. Countries with similar forest percentages to Romania experienced fewer conflicts, whereas countries with higher percentages, like Slovenia (61.65%) and Slovakia (39.86%), faced numerous human-bear conflicts due to the dense brown bear population. The management of bears served as a valuable indicator of the extent of damage caused by these animals. In Croatia, Sweden, Slovakia, and Slovenia, where 10- 16% of the bear population was harvested annually, lower levels of damage were reported. In contrast, Romania, with an annual harvest of only 2-3% of the bear population, experienced higher levels of damage. [ABSTRACT FROM AUTHOR]

Abstract Prey must balance resource acquisition with predator avoidance for survival and reproduction. To reduce risk of predation, prey may avoid areas with high predator use, but if they are unable to due to resource acquisition requirements, they may instead change their habitat use or movement speed to mitigate predation risk. Prey risk response may depend on spatially or temporally varying forage availability as well as seasonal variation in prey vulnerability and availability of alternate foods for predators. To quantify how prey respond to spatial and temporal variation in risk of brown bear predation, we examined Roosevelt elk (Cervus canadensis roosevelti) spatiotemporal behavior responses to brown bear (Ursus arctos) habitat use on Afognak and Raspberry islands, Alaska, using Global Positioning System location data during elk parturition (20 May–15 June), summer (16 June–20 September), and autumn (21 September–10 November). During parturition and summer, elk used forest and shrub landcover in areas of higher brown bear probability of use. During parturition, elk used areas with lower forage productivity in areas of higher bear probability of use, and movement speed decreased with higher bear probability of use, especially in shrub landcover. During summer, elk used areas with higher forage productivity in areas of higher brown bear probability of use. During autumn, elk were less likely to use areas with higher bear habitat probability of use across landcover categories and forage productivity. During summer and autumn, elk movement speed increased with higher brown bear probability of use. Elk behavioral response to risk of brown bear predation could increase energy expenditure and decrease their ability to acquire forage, therefore negatively impacting survival and reproduction with spatiotemporal variation in risk response potentially amplifying these impacts.

Despite the high density of brown bears (Ursus arctos piscator) on the Kamchatka peninsula their genetic variation has not been studied by STR analysis. Our aim was, therefore, to provide population data from the Kamchatka brown bear population applying a validated DNA profiling system. Twelve dinucleotide STRs commonly used in Western-European (WE) populations and four additional ones (G10C, G10J, G10O, G10X), were included. Template input ≥ 0.2 ng was successfully amplified. Measurements of precision, stutter and heterozygous balance showed that markers could be reliably genotyped applying the thresholds used for genotyping WE brown bears. However, locus G10X revealed an ancient allele-specific polymorphism that led to suboptimal amplification of all 174 bp alleles (Kamchatka and WE). Allele frequency estimates and forensic genetic parameters were obtained from 115 individuals successfully identified by genotyping 434 hair samples. All markers met the Hardy-Weinberg and linkage equilibrium expectations, and the power of discrimination ranged from 0.667 to 0.962. The total average probability of identity from the 15 STRs was 1.4 ×10−14 (FST = 0.05) while the total average probability of sibling identity was 6.0 ×10−6. Relationship tests revealed several parent-cub and full sibling pairs demonstrating that the marker set would be valuable for the study of family structures. The population data is the first of its kind from the Kamchatka brown bear population. Population pairwise FST`s revealed moderate genetic differentiation that mirrored the geographic distances to WE populations. The DNA profiling system, providing individual-specific profiles from non-invasive samples, will be useful for future monitoring and conservation purposes

Hibernation is a period of metabolic suppression utilized by many small and large mammal species to survive during winter periods. As the underlying cellular and molecular mechanisms remain incompletely understood, our study aimed to determine whether skeletal muscle myosin and its metabolic efficiency undergo alterations during hibernation to optimize energy utilization. We isolated muscle fibers from small hibernators, Ictidomys tridecemlineatus and Eliomys quercinus and larger hibernators, Ursus arctos and Ursus americanus. We then conducted loaded Mant-ATP chase experiments alongside X-ray diffraction to measure resting myosin dynamics and its ATP demand. In parallel, we performed multiple proteomics analyses. Our results showed a preservation of myosin structure in U. arctos and U. americanus during hibernation, whilst in I. tridecemlineatus and E. quercinus, changes in myosin metabolic states during torpor unexpectedly led to higher levels in energy expenditure of type II, fast-twitch muscle fibers at ambient lab temperatures (20 °C). Upon repeating loaded Mant-ATP chase experiments at 8 °C (near the body temperature of torpid animals), we found that myosin ATP consumption in type II muscle fibers was reduced by 77-107% during torpor compared to active periods. Additionally, we observed Myh2 hyper-phosphorylation during torpor in I. tridecemilineatus, which was predicted to stabilize the myosin molecule. This may act as a potential molecular mechanism mitigating myosin-associated increases in skeletal muscle energy expenditure during periods of torpor in response to cold exposure. [ABSTRACT FROM AUTHOR]

We analyzed handedness of brown bears (Ursus arctos), which is the tendency to differentially use the right or left forelimb for dexterous actions. Handedness in mammals is hypothesized to be an outcome of lateralization of neocortex function, which serves to increase cognitive capacity by reducing redundancy of function between left and right hemispheres. Handedness in brown bears would give insight into brown bear capacity for cognition and innovative behavior. We tallied brown bear forelimb use from videography of bears foraging on anadromous sockeye salmon (Oncorhynchus nerka) while aggregated at the Brooks River within Katmai National Park, Alaska, USA, during autumn 2022. Brown bears exhibited a significant propensity for handedness, a result driven primarily by brown bears using their right forelimb more often than their left to swat at conspecifics during social interactions. Under the model that neocortex lateralization increases cognitive capacity, the right-handedness we observed in brown bears is consistent with their capacity for problem solving and behavioral innovation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Forestry Society of Croatia / Sumarski List Hrvatskoga Sumarskoga Drustva is the property of Forestry Society of Croatia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Mammalian skeletons are largely formed before birth. Heterochronic changes in skeletal formation can be investigated by comparing the order of ossification for different elements of the skeleton. Due to the challenge of collecting prenatal specimens in viviparous taxa, opportunistically collected museum specimens provide the best material for studying prenatal skeletal development across many mammalian species. Previous studies have investigated ossification sequence in a range of mammalian species, but little is known about the pattern of bone formation in Carnivora. Carnivorans have diverse ecologies, diets, and biomechanical specializations and are well-suited for investigating questions in evolutionary biology. Currently, developmental data on carnivorans is largely limited to domesticated species. To expand available data on carnivoran skeletal development, we used micro-computed tomography (micro-CT) to non-invasively evaluate the degree of ossification in all prenatal carnivoran specimens housed in the Harvard Museum of Comparative Zoology. By coding the presence or absence of bones in each specimen, we constructed ossification sequences for each species. Parsimov-based genetic inference (PGi) was then used to identify heterochronic shifts between carnivoran lineages and reconstruct the ancestral ossification sequence of Carnivora. Results: We used micro-CT to study prenatal ossification sequence in six carnivora species: Eumetopias jubatus (Steller sea lion, n = 6), Herpestes javanicus (small Indian mongoose, n = 1), Panthera leo (lion, n = 1), Urocyon cinereoargenteus (gray fox, n = 1), Ursus arctos arctos (Eurasian brown bear, n = 1), and Viverricula indica (small Indian civet, n = 5). Due to the relatively later stage of collection for the available specimens, few heterochronic shifts were identified. Ossification sequences of feliform species showed complete agreement with the domestic cat. In caniforms, the bear and fox ossification sequences largely matched the dog, but numerous heterochronic shifts were identified in the sea lion. Conclusions: We use museum specimens to generate cranial and postcranial micro-CT data on six species split between the two major carnivoran clades: Caniformia and Feliformia. Our data suggest that the ossification sequence of domestic dogs and cats are likely good models for terrestrial caniforms and feliforms, respectively, but not pinnipeds. [ABSTRACT FROM AUTHOR]