Dave Garshelis

International Union for Conservation of Nature | IUCN · Bear Specialist Group

Sloth bears are non‐carnivorous yet they attack more people than any other bear. They often stand up and charge explosively if a person mistakenly gets too close. Here, we argue that their aggression toward humans is an extension of their behavior toward tigers, which are their only natural predator. Interactions between sloth bears and tigers have...

Color variation is a frequent evolutionary substrate for camouflage in small mammals, but the underlying genetics and evolutionary forces that drive color variation in natural populations of large mammals are mostly unexplained. The American black bear, Ursus americanus (U. americanus), exhibits a range of colors including the cinnamon morph, which...

At the most basic level, the assessment of a species’ status involves knowing where it occurs. Determining the presence of rare species is difficult, and can be further confounded by the presence of a more common look-alike species. We investigated one of the few places in the world where three species of bears have been reported to co-occur at a f...

Color variation is a frequent evolutionary substrate for camouflage in small mammals but the underlying genetics and evolutionary forces that drive color variation in natural populations of large mammals are mostly unexplained. The American black bear, Ursus americanus , exhibits a range of colors including the cinnamon morph which has a similar co...

An important rationale for legally farmed and synthetic wildlife products is that they reduce illegal, wild‐sourced trade by supplying markets with sustainable alternatives. For this to work, more established illegal‐product consumers must switch to legal alternatives than new legal‐product consumers switch to illegal wild products. Despite the wid...

Designing a population monitoring program for Asian bears presents challenges associated with their low densities and detectability, generally large home ranges, and logistical or resource constraints. The use of an occupancy-based method to monitor bear populations can be appropriate under certain conditions given the mechanistic relationship betw...

Efficient and effective monitoring methods are required to assess population status and gauge efficacy of conservation actions for threatened species. Here we review the spectrum of field methods useful for monitoring distribution, occupancy, abundance, and population trend for the five species of Asian terrestrial bears. Methods reviewed include e...

Many wildlife species are threatened in Asia, including the five species of terrestrial bears (Asiatic black, Ursus thibetanus; brown, U. arctos; sloth, Melursus ursinus; sun, Helarctos malayanus; giant panda, Ailuropoda melanoleuca): many populations of these bears are thought to be declining or imperiled by small population size. Here our aim is...

Changes in the distribution of a species can be used to as a metric of conservation status and to identify the loss or gain of isolated populations. This mapping process is a primary tool of the IUCN SSC Red List assessment. Most distribution maps are based on expert opinion or species distribution models based on a combination of species detection...

Populations of bears in Asia are vulnerable to extinction and effective monitoring is critical to measure and direct conservation efforts. Population abundance (local density) or growth (λ) are the most sensitive metrics to change. We discuss and recommend implementing spatially explicit capture-recapture (SCR), the current gold standard for densit...

Habitat modeling is one of the most common practices in ecology today, aimed at understanding complex associations between species and an array of environmental, bioclimatic, and anthropogenic factors. This review of studies of seven species of terrestrial bears (Ursidae) occupying four continents examines how habitat models have been employed, and...

Sun bears (Helarctos malayanus), arguably the least-known bear species, are endemic to Southeast Asia and are believed to be in rapid decline due to forest loss and poaching, which are severe threats across this region. It has been asserted that, unlike other forest-dependent, omnivorous bears, sun bears are especially sensitive to changes in fores...

Understanding wildlife consumption is essential for the design and evaluation of effective conservation interventions to reduce illegal trade. This requires understanding both the consumers themselves and those who influence their behaviour. For example, in markets for wildlife‐based medicines, both consumers and medical practitioners have a role i...

Wildlife management entails the manipulation of bottom-up and top-down forces that affect populations. For bear management in North America, both food availability (bottom-up) and hunting pressure (top-down) can limit population growth. Whereas seasonal and year-to-year variation in production of fruits and nuts (i.e., primary bear foods) has been...

The latest technologies associated with implantable physiological monitoring devices can record multiple channels of data (including: heart rates and rhythms, activity, temperature, impedance and posture), and coupled with powerful software applications, have provided novel insights into the physiology of animals in the wild. This perspective detai...

Bears have fascinated people since ancient times. The relationship between bears and humans dates back thousands of years, during which time we have also competed with bears for shelter and food. In modern times, bears have come under pressure through encroachment on their habitats, climate change, and illegal trade in their body parts, including t...

Bears have fascinated people since ancient times. The relationship between bears and humans dates back thousands of years, during which time we have also competed with bears for shelter and food. In modern times, bears have come under pressure through encroachment on their habitats, climate change, and illegal trade in their body parts, including t...

The integration of citizen scientists into ecological research is transforming how, where, and when data are collected, and expanding the potential scales of ecological studies. Citizen‐science projects can provide numerous benefits for participants while educating and connecting professionals with lay audiences, potentially increasing the acceptan...

Among the world’s large Carnivores, American black bears (Ursus americanus) are the foremost conservation success story. Populations have been expanding across North America because the species is adaptable and tolerant of living near people, and because management agencies in the U.S. and Canada controlled hunting and other human-sources of mortal...

The distribution of Asiatic black bears (hereafter ABB; Ursus thibetanus), sun bears (Helarctos malayanus) and sloth bears (Melursus ursinus) intersect in northeast (NE) India (Choudhury 2011, 2013). All 3 species were once recorded in Meghalaya, Assam, and Nagaland. Previously, we conducted workshops in these 3 states (Sharp et al. 2017), and dev...

Unmanned aircraft systems (UAS; i.e. 'drones') provide new opportunities for data collection in ecology, wildlife biology and conservation. Yet, several studies have documented behavioral or physiological responses to close-proximity UAS flights. We experimentally tested whether American black bears (Ursus americanus) habituate to repeated UAS expo...

As large areas of forest are lost throughout the tropics, prime habitat of many species decline and become fragmented. The island of Borneo is a prime example, with accelerated clearing of forests primarily for oil palm expansion. Borneo is recognized as an important stronghold for the conservation of the sun bear (Helarctos malayanus), but it is u...

Open-Access until Dec 29, 2018: https://authors.elsevier.com/a/1Y1TM15DJ~tX~Q Determining habitat requirements for the persistence of a wildlife population is especially difficult for wide-ranging, opportunist species. The American black bear (Ursus americanus) is one such species that is re-colonizing parts of its former range and colonizing new...

Multiple small populations of American black bears Ursus americanus, including the recently delisted Louisiana black bear subspecies U. a. luteolus, occupy a fragmented landscape in the Lower Mississippi Alluvial Valley, USA (LMAV). Populations include bears native to the LMAV, bears translocated from Minnesota during the 1960s, and recently reintr...

Biologgers can be used to monitor both human and animal physiology and behaviors, activity patterns, and/or envi-ronmental stressors. Monitoring of heart rates and rhythms, respiratory patterns, and activity in free-ranging bears can provide unique insights into physiological mechanisms. Such research can also influence the conservation of wildlife...

Roadways may negatively impact wildlife species through vehicular-related mortality and spatial displacement or obstruction. Here, we investigated physiological responses, which provide insights into the animal's perception of its environment. We deployed Global Positioning System (GPS)-collars in combination with cardiac biologgers on American bla...

Largely as a result of the expansion of oil palm Elaeis guineensis , forest fragmentation has occurred on a large scale in Borneo. There is much concern about how forest-dependent species, such as the Vulnerable sun bear Helarctos malayanus , can persist in this landscape. The absence of sufficient natural food in forest fragments could drive sun b...

Diversionary feeding uses food to lure animals away from areas where they are unwanted or could cause conflicts with people. With bears (Ursidae) increasingly attracted to human food sources worldwide, diversionary feeding represents a seemingly logical and publicly acceptable means of alleviating conflicts. Feeding wildlife is widely practiced in...

The American black bear (Ursus americanus) has been called a metabolic marvel6. In northern Minnesota, where we have conducted long-term physiological and ecological studies of this species, bears may remain in their winter dens for 6 months or more without eating, drinking, urinating or defecating and yet lose very little muscle mass2. We also fou...

Physiological monitoring of free-ranging wild animals is providing new insights into their adaptations to a changing environment. American black bears (Ursus americanus) are highly adaptable mammals, spending up to half the year hibernating, and the remainder of the year attempting to gain weight on a landscape with foods that vary seasonally and y...

Camera traps are increasingly used to assess the distribution of wildlife, including bears, throughout the Indian subcon-tinent and Southeast Asia. Accordingly, researchers must be able to determine with near certainty the species—and in our case the specific species of bear—that has been photographed. This can be difficult in areas occupied by sym...

Remarkably, American black bears (Ursus Americanus) are capable of varying their heart rates to coincide with their breathing, creating pauses of 30 seconds or more, yet they do not appear to suffer from embolic events. We evaluated some features of the clotting cascade of black bears, providing novel insights on the underlying mechanisms they evok...

Sloth bears (Melursus ursinus) historically occupied most of India, Sri Lanka, and Bangladesh, as well as a narrow strip of lowlands (Terai) in southern Nepal that stretches through West Bengal into Bhutan. During the 1980s they were lost from a key national park in western Nepal, and in the 1990s were entirely extirpated from Bangladesh. Along the...

Human-altered landscapes are thought to reduce habitat quality for many forest-dependent species, but some omnivorous, opportunist species take advantage of human-related food sources, such as garbage and crops. It is unknown, however, whether anthropogenic foods can sustain populations in areas with relatively little natural habitat. We studied (2...

Unmanned aerial vehicles (UAVs) have the potential to revolutionize the way research is conducted in many scientific fields [1, 2]. UAVs can access remote or difficult terrain [3], collect large amounts of data for lower cost than traditional aerial methods, and facilitate observations of species that are wary of human presence [4]. Currently, desp...

Significant information gaps exist regarding the status of polar bears, especially with respect to the impacts of climate change, across large portions of the Arctic. To obtain an updated abundance estimate for the Foxe Basin population, we conducted comprehensive aerial surveys during the 2009 and 2010 ice-free seasons, when bears are confined to...

Human activities and variation in habitat quality and configuration have been shown to influence space use patterns in many species, but few studies have documented the physiological responses of free-ranging animals to these factors. We combined remote biologger technology, capturing continuous heart rate values, with locational data from GPS coll...

BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological,...

Background Numerous innovations for the management and collection of ¿big data¿ have arisen in the field of medicine, including implantable computers and sensors, wireless data transmission, and web-based repositories for collecting and organizing information. Recently, human clinical devices have been deployed in captive and free-ranging wildlife...

Solitary, facultative migrating animals must make decisions each year on whether, when, and where to migrate. Factors influencing individuals in their movement choices are poorly understood. American black bears (Ursus americanus Pallas, 1780) commonly migrate in late summer to areas of concentrated foods before winter denning; some bears also move...

Asiatic black bears (Ursus thibetanus) are declining throughout much of their range. In China they are partially protected by a nature reserve system and rely heavily on hard mast as a food source prior to winter denning. Bears may compensate for mast shortages by raiding agricultural crops and killing livestock, mainly outside reserves where they...

Development of efficient techniques for monitoring wildlife is a priority in the Arctic, where the impacts of climate change are acute and remoteness and logistical constraints hinder access. We evaluated high resolution satellite imagery as a tool to track the distribution and abundance of polar bears. We examined satellite images of a small islan...

Indigenous belief systems and informal institutions that result in the conservation of wild species or sites exemplify biocultural conservation. The erosion of cultural beliefs and practices can have adverse, often severe, consequences for biodiversity. We explored the relationships among informal institutions, religion, and human attitudes toward...

Sexually stimulating behaviors that are not linked to reproduction are rare among non-human (especially non-primate) mammals. Such behaviors may have a function in the hierarchy of social species. In solitary species, such behaviors are more enigmatic, and possibly indicative of something abnormal. Here, we report on a case of two male brown bears,...

Human-bear conflicts cause annoyance, financial losses, injuries and even death to people. In poorer parts of the world, conflicts with bears can affect local economies. Retaliation against bears may threaten the future of small, isolated populations. Our survey of the world's bear experts revealed that the problem is worsening in terms of severity...

Capture-based studies of the Western Hudson Bay (WH) polar bear population in Canada have reported declines in abundance, survival, and body condition, but these findings are inconsistent with the perceptions of local people. To address this uncertainty about current status, we conducted a comprehensive aerial survey of this population during Augus...

Sea otters (Enhydra lutris) suffered major mortality after the Exxon Valdez oil spill in Prince William Sound, Alaska, 1989. We evaluate the contention that their recovery spanned over two decades. A model based on the otter age-at-death distribution suggested a large, spill-related population sink, but this has never been found, and other model pr...

Asiatic black bears (Ursus thibetanus) and sun bears (Helarctos malayanus) are ecologically similar and coexist extensively across Southeast Asia. We used foraging signs identified to bear species to examine their food selection and dietary overlap relative to food abundance, nutrition, and phenology in 3 habitats in Thailand. We posited, based on...

The American black bear can hibernate for up to 6 months. During this period they do not eat, drink, urinate, or defecate: they elicit minimal movements and typically do not leave their dens. Still, they lose minimal skeletal muscle mass and strength, and do not suffer any adverse consequences of either starvation or dehydration. In previous report...

Even mildly hypothermic body or limb temperatures can retard healing processes in mammals. Despite this, we observed that hibernating American black bears (Ursus americanus Pallas, 1780) elicit profound abilities in mounting inflammatory responses to infection and/or foreign bodies. In addition, they resolve injuries during hibernation while mainta...

We present a fully implantable, chronic system for untethered neuroscience research in freely behaving animals. The system infrastructure provides an experimental toolkit for recording electrical signals and activating neural tissues via a neurostimulator. This system provides the ability to investigate the dynamic behavior of neural circuits witho...

Count-based indices and distance sampling are widely used to monitor primate populations. Indices are often confounded by variation in detectability, whereas distance sampling is generally ineffective with species that flee or hide from observers and where it is difficult to accurately measure detection distances. We tested occupancy modeling as a...

Hibernating female bear video 1. Hibernating female bear with cubs prior to tranquilization March 2008.

Hibernating female bear video 3. Bear 3 prior to tranquilization in March 2009 with audible cub sounds.

Hibernating female bear video 2. Bear 3 prior to tranquilization on 18-Dec-2009.

Hibernating female bear video 4. Female bear with cubs March 2009 with audible cub sounds.

Bears are among the most physiologically remarkable mammals. They spend half their life in an active state and the other half in a state of dormancy without food or water, and without urinating, defecating, or physical activity, yet can rouse and defend themselves when disturbed. Although important data have been obtained in both captive and wild b...

We used tetracycline biomarking, augmented with genetic methods to estimate the size of an American black bear (Ursus americanus) population on an island in Southeast Alaska. We marked 132 and 189 bears that consumed remote, tetracycline-laced baits in 2 different years, respectively, and observed 39 marks in 692 bone samples subsequently collected...

The American black bear maintains lean body mass for months without food during winter denning. We asked whether changes in the growth hormone/insulin-like growth factor-I (GH-IGF-I) axis may contribute to this remarkable adaptation to starvation. Serum IGF-I levels were measured by radioimmunoassay, and IGF-binding proteins (IGFBPs) were analyzed...

Few attempts have been made to estimate numbers and densities of Andean bears (Tremarctos ornatus). It is understandable that the many challenges involved in these efforts have made it difficult to produce rigorous estimates. A crude estimate of 20,000 Andean bears was derived by extrapolating the lowest observed density of American black bears (Ur...

American black bears frequently abandon their home ranges in late summer and move to feeding areas to fatten themselves for hibernation. We examined seasonal movements of 206 radio-collared bears in north-central Minnesota during 1981–1990. We exploited the variability in this long-term data set to test tradeoffs for animals leaving their home rang...

Known reproductive histories of female radio-collared black bears (Ursus americanus) in Minnesota were matched against the spacing of growth layers in stained thin sections of their teeth. Light-staining bands of cementum, deposited during the summer months, were relatively narrow during years when females were raising cubs. Because females in this...

Human-wildlife conflicts often spur retaliatory killing, which may be a major threat to some wildlife species. Asiatic black bears depredate crops and livestock and also attack humans. We investigated whether human–bear conflicts in Sichuan Province, southwestern China, resulted in increased bear poaching. We conducted semi-structured interviews wi...