Determinants of Home Range Size for Polar Bears (Ursus maritimus)

The mean home range size of female polar bears ( Ursus maritimus ; 125 100 km² ± 11 800; n  = 93) is substantially larger than the predicted value (514 km²) for a terrestrial carnivore of similar weight. To understand this difference, we correlated home range size and sea ice characteristics. Home range size was related to (i) the ratio of land vs. sea within a given home range (42% of explained variance), and (ii) seasonal variation in ice cover (24%). Thus, bears using land during the ice-free season had larger home ranges and bears living in areas of great seasonal variation in ice cover also had larger home ranges. In another analysis we investigated how variation in a bear's environment in space and time affects its choice of home range. We found that polar bears adjusted the size of their home range according to the amount of annual and seasonal variation within the centre of their home range. For example, polar bears experiencing unpredictable seasonal and annual ice tended to increase their home range size if increasing home range size resulted in reducing variation in seasonal and annual ice. Polar bears make trade-offs between alternate space-use strategies. Large home ranges occur when variable ice cover is associated with more seals but also a more unpredictable distribution of those seals.     

Population substructure and space use of Foxe Basin polar bears

Climate change has been identified as a major driver of habitat change, particularly for sea ice-dependent species such as the polar bear (Ursus maritimus). Population structure and space use of polar bears have been challenging to quantify because of their circumpolar distribution and tendency to range over large areas. Knowledge of movement patterns, home range, and habitat is needed for conservation and management. This is the first study to examine the spatial ecology of polar bears in the Foxe Basin management unit of Nunavut, Canada. Foxe Basin is in the mid-Arctic, part of the seasonal sea ice ecoregion and it is being negatively affected by climate change. Our objectives were to examine intrapopulation spatial structure, to determine movement patterns, and to consider how polar bear movements may respond to changing sea ice habitat conditions. Hierarchical and fuzzy cluster analyses were used to assess intrapopulation spatial structure of geographic position system satellite-collared female polar bears. Seasonal and annual movement metrics (home range, movement rates, time on ice) and home-range fidelity (static and dynamic overlap) were compared to examine the influence of regional sea ice on movements. The polar bears were distributed in three spatial clusters, and there were differences in the movement metrics between clusters that may reflect sea ice habitat conditions. Within the clusters, bears moved independently of each other. Annual and seasonal home-range fidelity was observed, and the bears used two movement patterns: on-ice range residency and annual migration. We predict that home-range fidelity may decline as the spatial and temporal predictability of sea ice changes. These new findings also provide baseline information for managing and monitoring this polar bear population.     

Functional responses in polar bear habitat selection

Habitat selection may occur in situations in which animals experience a trade-off, e.g. between the use of habitats with abundant forage and the use of safer retreat habitats with little forage. Such trade-offs may yield relative habitat use conditional on the relative availability of the different habitat types, as proportional use of foraging habitat may exceed proportional availability when foraging habitat is scarce, but be less than availability when foraging habitat is abundant. Hence, trade-offs in habitat use may result in functional responses in habitat use (i.e. change in relative use with changing availability). We used logistic and log-linear models to model functional responses in female polar bear habitat use based on satellite telemetry data from two contiguous populations; one near shore inhabiting sea ice within fjords, and one inhabiting pelagic drift ice. Open ice, near the ice edge, is a highly dynamic habitat hypothesised to be important polar bear habitat due to high prey availability. In open ice-polar bears may experience a high energetic cost of movements and risk drifting away from the main ice field (i.e. trade off between feeding and energy saving or safety). If polar bears were constrained by ice dynamics we therefore predicted use of retreat habitats with greater ice coverage relative to habitats used for hunting. The polar bears demonstrated season and population specific functional responses in habitat use, likely reflecting seasonal and regional variation in use of retreat and foraging habitats. We suggest that in seasons with functional responses in habitat use, polar bear space use and population distribution may not be a mere reflection of prey availability but rather reflect the alternate allocation of time in hunting and retreat habitats.     

Observations of mortality associated with extended open-water swimming by polar bears in the Alaskan Beaufort Sea

During aerial surveys in September 1987–2003, a total of 315 live polar bears were observed with 12 (3.8%) animals in open water, defined for purposes of this analysis as marine waters >2 km north of the Alaska Beaufort Sea coastline or associated barrier islands. No polar bear carcasses were observed. During aerial surveys in early September, 2004, 55 polar bears (Ursus maritimus) were seen, 51 were alive and of those 10 (19.9%) were in open water. In addition, four polar bear carcasses were seen floating in open water and had, presumably, drowned. Average distance from land and pack ice edge for live polar bears swimming in open water in 2004 (n=10) were 8.3±3.0 and 177.4±5.1 km, respectively. We speculate that mortalities due to offshore swimming during late-ice (or mild ice) years may be an important and unaccounted source of natural mortality given energetic demands placed on individual bears engaged in long-distance swimming. We further suggest that drowning-related deaths of polar bears may increase in the future if the observed trend of regression of pack ice and/or longer open water periods continues.     

Accounting for phenology in the analysis of animal movement

The analysis of animal tracking data provides important scientific understanding and discovery in ecology. Observations of animal trajectories using telemetry devices provide researchers with information about the way animals interact with their environment and each other. For many species, specific geographical features in the landscape can have a strong effect on behavior. Such features may correspond to a single point (eg, dens or kill sites), or to higher dimensional subspaces (eg, rivers or lakes). Features may be relatively static in time (eg, coastlines or home‐range centers), or may be dynamic (eg, sea ice extent or areas of high‐quality forage for herbivores). We introduce a novel model for animal movement that incorporates active selection for dynamic features in a landscape. Our approach is motivated by the study of polar bear (Ursus maritimus) movement. During the sea ice melt season, polar bears spend much of their time on sea ice above shallow, biologically productive water where they hunt seals. The changing distribution and characteristics of sea ice throughout the year mean that the location of valuable habitat is constantly shifting. We develop a model for the movement of polar bears that accounts for the effect of this important landscape feature. We introduce a two‐stage procedure for approximate Bayesian inference that allows us to analyze over 300 000 observed locations of 186 polar bears from 2012 to 2016. We use our model to estimate a spatial boundary of interest to wildlife managers that separates two subpopulations of polar bears from the Beaufort and Chukchi seas.     

Consequences of long-distance swimming and travel over deep-water pack ice for a female polar bear during a year of extreme sea ice retreat

Polar bears (Ursus maritimus) prefer to live on Arctic sea ice but may swim between ice floes or between sea ice and land. Although anecdotal observations suggest that polar bears are capable of swimming long distances, no data have been available to describe in detail long distance swimming events or the physiological and reproductive consequences of such behavior. Between an initial capture in late August and a recapture in late October 2008, a radio-collared adult female polar bear in the Beaufort Sea made a continuous swim of 687 km over 9 days and then intermittently swam and walked on the sea ice surface an additional 1,800 km. Measures of movement rate, hourly activity, and subcutaneous and external temperature revealed distinct profiles of swimming and walking. Between captures, this polar bear lost 22% of her body mass and her yearling cub. The extraordinary long distance swimming ability of polar bears, which we confirm here, may help them cope with reduced Arctic sea ice. Our observation, however, indicates that long distance swimming in Arctic waters, and travel over deep water pack ice, may result in high energetic costs and compromise reproductive fitness.     

Female polar bears, Ursus maritimus, on the Barents Sea drift ice: walking the treadmill

For animals in dynamic habitats, the contribution of passive (i.e. by wind or current) and active (movements by the animals themselves) displacement determines whether their space use reflects physical or adaptive behavioural processes. Polar bears in the Barents Sea undertake extensive annual migrations in a habitat that is highly dynamic because of continuous sea ice drift. Using combined information from satellite telemetry, satellite images and atmospheric pressure recordings, we estimated the contribution of sea ice drift and movements in the monthly net displacement of female polar bears. We found that movements, and thus behavioural processes, were dominant. Net displacement was directed northwards during summer ice retreat and southwards during winter ice advance. Conversely, movements were directed northwards counteracting a continuous southward drift. Acting as a treadmill, ice drift probably increased the energetic cost of migrations relative to that expected from observed net displacement distances; this suggests that pelagic and adjacent near-shore bears, on stable land-fast ice, have different energy costs. Little concordance between ice drift rates and net displacement and movement rates suggest that polar bears do not adjust their displacement relative to attractive areas with fixed locations, but rather adjust their movements to local habitat suitability. Furthermore, selective use of less dynamic drift ice when with cubs-of-the-year, and use of terrestrial denning areas, appear to be behavioural adaptations to the dynamics of the Barents Sea drift ice. Hence, understanding the behaviour and ecology of animals inhabiting dynamic habitats necessitates incorporation of both dynamic and static habitat variables. Copyright 2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.      

Longer ice-free seasons increase the risk of nest depredation by polar bears for colonial breeding birds in the Canadian Arctic

Northern polar regions have warmed more than other parts of the globe potentially amplifying the effects of climate change on biological communities. Ice-free seasons are becoming longer in many areas, which has reduced the time available to polar bears (Ursus maritimus) to hunt for seals and hampered bears’ ability to meet their energetic demands. In this study, we examined polar bears’ use of an ancillary prey resource, eggs of colonial nesting birds, in relation to diminishing sea ice coverage in a low latitude region of the Canadian Arctic. Long-term monitoring reveals that bear incursions onto common eider (Somateria mollissima) and thick-billed murre (Uria lomvia) nesting colonies have increased greater than sevenfold since the 1980s and that there is an inverse correlation between ice season length and bear presence. In surveys encompassing more than 1000 km of coastline during years of record low ice coverage (2010–2012), we encountered bears or bear sign on 34% of eider colonies and estimated greater egg loss as a consequence of depredation by bears than by more customary nest predators, such as foxes and gulls. Our findings demonstrate how changes in abiotic conditions caused by climate change have altered predator–prey dynamics and are leading to cascading ecological impacts in Arctic ecosystems.     

Movements of female polar bears (<Emphasis Type="Italic">Ursus maritimus</Emphasis>) in the East Greenland pack ice

The movements of two adult female polar bears ( Ursus maritimus) in East Greenland and the Greenland Sea area were studied by use of satellite telemetry between the fall of 1994 and the summer of 1998. One female was tracked for 621 days, the other for 1,415 days. During this time the females used maternity dens on land. If denning periods on land were excluded, the two females used between 73% and 100% of the tracking time offshore where they were able to navigate in the dynamic pack ice and counteract the fast southward movement of the ice (up to 30 km/h) in the East Greenland Current. Mean monthly movement rates varied between 0.32 and 0.76km/h. Both bears had very large home ranges (242,000 and 468,000 km ²) within the dynamic pack ice of the Greenland Sea. The facts that the bears made extensive use of the offshore sea ice and that there is a marked reduction of the Greenland Sea ice call for a closer monitoring of the effects of this change on the East Greenland polar bear population.     

Are polar bear habitat resource selection functions developed from 1985–1995 data still useful?

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Increased Arctic sea ice drift alters adult female polar bear movements and energetics

Recent reductions in thickness and extent have increased drift rates of Arctic sea ice. Increased ice drift could significantly affect the movements and the energy balance of polar bears (Ursus maritimus) which forage, nearly exclusively, on this substrate. We used radio‐tracking and ice drift data to quantify the influence of increased drift on bear movements, and we modeled the consequences for energy demands of adult females in the Beaufort and Chukchi seas during two periods with different sea ice characteristics. Westward and northward drift of the sea ice used by polar bears in both regions increased between 1987–1998 and 1999–2013. To remain within their home ranges, polar bears responded to the higher westward ice drift with greater eastward movements, while their movements north in the spring and south in fall were frequently aided by ice motion. To compensate for more rapid westward ice drift in recent years, polar bears covered greater daily distances either by increasing their time spent active (7.6%–9.6%) or by increasing their travel speed (8.5%–8.9%). This increased their calculated annual energy expenditure by 1.8%–3.6% (depending on region and reproductive status), a cost that could be met by capturing an additional 1–3 seals/year. Polar bears selected similar habitats in both periods, indicating that faster drift did not alter habitat preferences. Compounding reduced foraging opportunities that result from habitat loss; changes in ice drift, and associated activity increases, likely exacerbate the physiological stress experienced by polar bears in a warming Arctic.     

Pattern of space use by female black bears in the White River National Wildlife Refuge,Arkansas, USA

The manner in which space is used by animals may influence several aspects of biology, including the pattern of resource use and intra-specific competition. We monitored 16 radio-collared female black bears (Ursus americanus) for 9,216 radio days during 1993–1995 in the White River National Wildlife Refuge (WRNWR), Arkansas, U.S.A. to investigate space use patterns. Annual home ranges (95% convex polygon) ranged from 2.10 to 11.34 km² with a mean (± SD) size of 4.90 (± 2.09) km² (n = 16). Largest home ranges were occupied by 2 females with yearlings during one year of study. Home ranges among neighbouring bears overlapped considerably. Although bears maintained larger home ranges during summer, the size of home range did not differ among seasons (P > 0.50). Our estimates of home range size for female black bears were smaller than those obtained in a study of the same population during 1979–1982. Because the size of the bear population at WRNWR was substantially smaller (about 130 bears) during 1979–1982 compared to the present population of ≥348 bears, these results suggested that population density and size of female black bear home ranges may be negatively correlated. Conservation implications of density-dependent space use pattern are also discussed.     

Increased Land Use by Chukchi Sea Polar Bears in Relation to Changing Sea Ice Conditions

Recent observations suggest that polar bears (Ursus maritimus) are increasingly using land habitats in some parts of their range, where they have minimal access to their preferred prey, likely in response to loss of their sea ice habitat associated with climatic warming. We used location data from female polar bears fit with satellite radio collars to compare land use patterns in the Chukchi Sea between two periods (1986–1995 and 2008–2013) when substantial summer sea-ice loss occurred. In both time periods, polar bears predominantly occupied sea-ice, although land was used during the summer sea-ice retreat and during the winter for maternal denning. However, the proportion of bears on land for > 7 days between August and October increased between the two periods from 20.0% to 38.9%, and the average duration on land increased by 30 days. The majority of bears that used land in the summer and for denning came to Wrangel and Herald Islands (Russia), highlighting the importance of these northernmost land habitats to Chukchi Sea polar bears. Where bears summered and denned, and how long they spent there, was related to the timing and duration of sea ice retreat. Our results are consistent with other studies supporting increased land use as a common response of polar bears to sea-ice loss. Implications of increased land use for Chukchi Sea polar bears are unclear, because a recent study observed no change in body condition or reproductive indices between the two periods considered here. This result suggests that the ecology of this region may provide a degree of resilience to sea ice loss. However, projections of continued sea ice loss suggest that polar bears in the Chukchi Sea and other parts of the Arctic may increasingly use land habitats in the future, which has the potential to increase nutritional stress and human-polar bear interactions.     

Movements of two Svalbard polar bears recorded using geographical positioning system satellite transmitters

Until recently, studies on polar bear (Ursus maritimus) movements and space use have used data collected by satellite telemetry collars that provided positions infrequently (typically weekly) and with low precision (by Doppler Shift method). A new generation of transmitters incorporated into collars use the Global Positioning System (GPS) to provide highly accurate positions, and have the ability to provide many positions per day. We used data from two GPS collars fitted to female polar bears, that attempted to collect six positions per day (4-h apart) for 546 days (from April 2000 to September 2001) and 413 days (from April 2000 to May 2001) to estimate how estimated speed of movement and home range size increase with increasing number of data points. Using all the positions, we estimated that the bears moved a minimum of 14.3 and 15.8 km per day on average. The fractal dimension (D) of the movement pathways for the two bears were D = 1.28 and 1.31, respectively, indicating low tortousity of the movements. Their minimum estimated annual home range areas were 20,794 and 112,183 km². Simulations showed that a commonly used sampling regime of one location every 6th day would have significantly underestimated the movement rates and the home range sizes compared to our estimates. We also used the high accuracy of GPS positions to look at distances moved within 4-h periods. Maximum movement rate during a 4-h period for the two bears was 4.21 and 4.58 km/h, respectively. Variation in median values by month was significant (0.01 km/h in November for N23476 to 1.48 km/h in December for N7955). Diurnal variation was observed to differ between defined periods.     

Increasing nest predation will be insufficient to maintain polar bear body condition in the face of sea ice loss

Climate change can influence interspecific interactions by differentially affecting species‐specific phenology. In seasonal ice environments, there is evidence that polar bear predation of Arctic bird eggs is increasing because of earlier sea ice breakup, which forces polar bears into nearshore terrestrial environments where Arctic birds are nesting. Because polar bears can consume a large number of nests before becoming satiated, and because they can swim between island colonies, they could have dramatic influences on seabird and sea duck reproductive success. However, it is unclear whether nest foraging can provide an energetic benefit to polar bear populations, especially given the capacity of bird populations to redistribute in response to increasing predation pressure. In this study, we develop a spatially explicit agent‐based model of the predator–prey relationship between polar bears and common eiders, a common and culturally important bird species for northern peoples. Our model is composed of two types of agents (polar bear agents and common eider hen agents) whose movements and decision heuristics are based on species‐specific bioenergetic and behavioral ecological principles, and are influenced by historical and extrapolated sea ice conditions. Our model reproduces empirical findings that polar bear predation of bird nests is increasing and predicts an accelerating relationship between advancing ice breakup dates and the number of nests depredated. Despite increases in nest predation, our model predicts that polar bear body condition during the ice‐free period will continue to decline. Finally, our model predicts that common eider nests will become more dispersed and will move closer to the mainland in response to increasing predation, possibly increasing their exposure to land‐based predators and influencing the livelihood of local people that collect eider eggs and down. These results show that predator–prey interactions can have nonlinear responses to changes in climate and provides important predictions of ecological change in Arctic ecosystems.     

Habitat‐mediated timing of migration in polar bears: an individual perspective

Migration phenology is largely determined by how animals respond to seasonal changes in environmental conditions. Our perception of the relationship between migratory behavior and environmental cues can vary depending on the spatial scale at which these interactions are measured. Understanding the behavioral mechanisms behind population‐scale movements requires knowledge of how individuals respond to local cues. We show how time‐to‐event models can be used to predict what factors are associated with the timing of an individual's migratory behavior using data from GPS collared polar bears (Ursus maritimus) that move seasonally between sea ice and terrestrial habitats. We found the concentration of sea ice that bears experience at a local level, along with the duration of exposure to these conditions, was most associated with individual migration timing. Our results corroborate studies that assume thresholds of >50% sea ice concentration are necessary for suitable polar bear habitat; however, continued periods (e.g., days to weeks) of exposure to suboptimal ice concentrations during seasonal melting were required before the proportion of bears migrating to land increased substantially. Time‐to‐event models are advantageous for examining individual movement patterns because they account for the idea that animals make decisions based on an accumulation of knowledge from the landscapes they move through and not simply the environment they are exposed to at the time of a decision. Understanding the migration behavior of polar bears moving between terrestrial and marine habitat, at multiple spatiotemporal scales, will be a major aspect of quantifying observed and potential demographic responses to climate‐induced environmental changes.     

Effects of climate warming on polar bears: a review of the evidence

Climate warming is causing unidirectional changes to annual patterns of sea ice distribution, structure, and freeze‐up. We summarize evidence that documents how loss of sea ice, the primary habitat of polar bears (Ursus maritimus), negatively affects their long‐term survival. To maintain viable subpopulations, polar bears depend on sea ice as a platform from which to hunt seals for long enough each year to accumulate sufficient energy (fat) to survive periods when seals are unavailable. Less time to access to prey, because of progressively earlier breakup in spring, when newly weaned ringed seal (Pusa hispida) young are available, results in longer periods of fasting, lower body condition, decreased access to denning areas, fewer and smaller cubs, lower survival of cubs as well as bears of other age classes and, finally, subpopulation decline toward eventual extirpation. The chronology of climate‐driven changes will vary between subpopulations, with quantifiable negative effects being documented first in the more southerly subpopulations, such as those in Hudson Bay or the southern Beaufort Sea. As the bears' body condition declines, more seek alternate food resources so the frequency of conflicts between bears and humans increases. In the most northerly areas, thick multiyear ice, through which little light penetrates to stimulate biological growth on the underside, will be replaced by annual ice, which facilitates greater productivity and may create habitat more favorable to polar bears over continental shelf areas in the short term. If the climate continues to warm and eliminate sea ice as predicted, polar bears will largely disappear from the southern portions of their range by mid‐century. They may persist in the northern Canadian Arctic Islands and northern Greenland for the foreseeable future, but their long‐term viability, with a much reduced global population size in a remnant of their former range, is uncertain.     

Effects of Earlier Sea Ice Breakup on Survival and Population Size of Polar Bears in Western Hudson Bay

ABSTRACT Some of the most pronounced ecological responses to climatic warming are expected to occur in polar marine regions, where temperature increases have been the greatest and sea ice provides a sensitive mechanism by which climatic conditions affect sympagic (i.e., with ice) species. Population-level effects of climatic change, however, remain difficult to quantify. We used a flexible extension of Cormack-Jolly-Seber capture-recapture models to estimate population size and survival for polar bears (Ursus maritimus), one of the most ice-dependent of Arctic marine mammals. We analyzed data for polar bears captured from 1984 to 2004 along the western coast of Hudson Bay and in the community of Churchill, Manitoba, Canada. The Western Hudson Bay polar bear population declined from 1,194 (95% CI = 1,020-1,368) in 1987 to 935 (95% CI = 794-1,076) in 2004. Total apparent survival of prime-adult polar bears (5–19 yr) was stable for females (0.93; 95% CI = 0.91-0.94) and males (0.90; 95% CI = 0.88-0.91). Survival of juvenile, subadult, and senescent-adult polar bears was correlated with spring sea ice breakup date, which was variable among years and occurred approximately 3 weeks earlier in 2004 than in 1984. We propose that this correlation provides evidence for a causal association between earlier sea ice breakup (due to climatic warming) and decreased polar bear survival. It may also explain why Churchill, like other communities along the western coast of Hudson Bay, has experienced an increase in human-polar bear interactions in recent years. Earlier sea ice breakup may have resulted in a larger number of nutritionally stressed polar bears, which are encroaching on human habitations in search of supplemental food. Because western Hudson Bay is near the southern limit of the species' range, our findings may foreshadow the demographic responses and management challenges that more northerly polar bear populations will experience if climatic warming in the Arctic continues as projected.     

Range contraction and increasing isolation of a polar bear subpopulation in an era of sea‐ice loss

Climate change is expected to result in range shifts and habitat fragmentation for many species. In the Arctic, loss of sea ice will reduce barriers to dispersal or eliminate movement corridors, resulting in increased connectivity or geographic isolation with sweeping implications for conservation. We used satellite telemetry, data from individually marked animals (research and harvest), and microsatellite genetic data to examine changes in geographic range, emigration, and interpopulation connectivity of the Baffin Bay (BB) polar bear (Ursus maritimus) subpopulation over a 25‐year period of sea‐ice loss. Satellite telemetry collected from n = 43 (1991–1995) and 38 (2009–2015) adult females revealed a significant contraction in subpopulation range size (95% bivariate normal kernel range) in most months and seasons, with the most marked reduction being a 70% decline in summer from 716,000 km² (SE 58,000) to 211,000 km² (SE 23,000) (p < .001). Between the 1990s and 2000s, there was a significant shift northward during the on‐ice seasons (2.6^° shift in winter median latitude, 1.1^° shift in spring median latitude) and a significant range contraction in the ice‐free summers. Bears in the 2000s were less likely to leave BB, with significant reductions in the numbers of bears moving into Davis Strait (DS) in winter and Lancaster Sound (LS) in summer. Harvest recoveries suggested both short and long‐term fidelity to BB remained high over both periods (83–99% of marked bears remained in BB). Genetic analyses using eight polymorphic microsatellites confirmed a previously documented differentiation between BB, DS, and LS; yet weakly differentiated BB from Kane Basin (KB) for the first time. Our results provide the first multiple lines of evidence for an increasingly geographically and functionally isolated subpopulation of polar bears in the context of long‐term sea‐ice loss. This may be indicative of future patterns for other polar bear subpopulations under climate change.     

Observations of a wild polar bear (<Emphasis Type="Italic">Ursus maritimus</Emphasis>) successfully fishing Arctic charr (<Emphasis Type="Italic">Salvelinus alpinus</Emphasis>) and Fourhorn sculpin (<Emphasis Type="Italic">Myoxocephalus quadricornis</Emphasis>)

Polar bears, Ursus maritimus, throughout their range, are nutritionally dependent on ringed (Phoca hispida) and bearded seals (Erignathus barbatus), which are predominantly caught on the sea ice. Other marine prey species are caught and consumed, but less frequently. As the annual sea ice retreats, polar bears throughout their range are forced ashore, where they mostly live off their stored adipose tissue. However, while land-bound they have been observed catching birds and terrestrial mammals. Although polar bears evolved from brown bears (U. arctos), direct observations of polar bears diving for and catching fish have not been reported. Here, we document observations of a young male polar bear catching Arctic charr (Salvelinus alpinus) and Fourhorn sculpin (Myoxocephalus quadricornis) by diving in Creswell Bay, Nunavut. We recorded six search bouts, where six fish were caught during dives, which were preceded by a snorkel. The average dive and snorkel length was (mean ± SD) 13 ± 5 and 6 ± 2 s, respectively.