Polar bears hunt primarily by waiting motionless beside breathing holes in the sea ice, a technique called still-hunting that accounts for the vast majority of their hunts. In one field study, roughly three-quarters of observed hunts were still-hunts, with the remainder being active stalks across the ice. Their success depends on patience, acute senses, and a landscape of frozen sea that is increasingly difficult to count on.
Still-Hunting and Stalking on the Sea Ice
Ringed seals are the staple of the polar bear diet across most of the Arctic, and the way bears catch them reflects how seals live. Ringed seals maintain breathing holes in the sea ice, surfacing periodically for air. A polar bear locates one of these holes and lies beside it, sometimes for hours, waiting for the seal to surface. In a study of 288 hunts observed during midsummer, 233 were still-hunts and 65 were stalks, making the patient waiting game far more common than the active pursuit.1Canadian Journal of Zoology. Midsummer observations on the behavior of wild polar bears (Ursus maritimus) When a seal surfaces, the bear strikes with its forepaw, hooking the seal and dragging it onto the ice.
Stalking looks very different. A bear spots a seal hauled out on the ice, often basking near its breathing hole, and approaches slowly with its body pressed low. Bears sometimes use pressure ridges or ice features as cover, creeping forward in bursts when the seal drops its head. The final rush covers the last several meters at speed. Stalking tends to become more common later in spring, when seals haul out more frequently to bask, pup, and molt. Tracking data show that bears shift from stationary behavior toward active olfactory searching as the season progresses, likely reflecting this change in seal availability.2PubMed Central. Drivers of polar bear behavior and the possible effects of prey availability on foraging strategy
How Bears Find Their Prey
Smell is the polar bear’s primary tool for locating seals. Their sense of smell is powerful enough to detect a seal’s breathing hole under snow from a considerable distance across flat, featureless ice. Movement-tracking studies have found that bears spend roughly half their time in a stationary drift state, about 29 percent in olfactory search, and about 24 percent in area-restricted search, a mode where they concentrate their movement in a small area after detecting something promising.3PubMed Central. Drivers of polar bear behavior and the possible effects of prey availability on foraging strategy That large chunk of time spent motionless makes sense given how much still-hunting dominates their repertoire.
Bears also use their hearing and can detect the scratch of seal claws on ice or the sound of breathing at a hole. Their eyesight is roughly comparable to a human’s, functional for spotting a dark seal against white ice at moderate distances but not the main sense driving their hunts. On the ice, where wind carries scent across long open stretches, the nose does most of the work.
Why Blubber Matters More Than Meat
When a polar bear kills a ringed seal, it often eats the blubber first and may leave the lean muscle behind entirely, especially if food is plentiful. This is not wastefulness. A kilogram of ringed seal blubber contains about six times the digestible energy of a kilogram of ringed seal muscle.4Canadian Journal of Zoology. Digestibility of ringed seals by the polar bear Blubber is nearly all fat with very little water, and polar bears digest it with remarkable efficiency, absorbing over 97 percent of the fat they consume. Muscle, by contrast, is about 70 percent water, less digestible, and far less energy-dense.
This preference shapes the entire food web around a polar bear kill. Arctic foxes, gulls, and ravens scavenge the protein-rich carcass scraps that the bear leaves behind. For the bear, the priority is maximizing calories per unit of handling time, and blubber delivers on that math overwhelmingly. A well-fed bear in spring, when seal pups with their thick fat layers are available, can build up fat reserves that sustain it through months of leaner times.
The Surprisingly High Cost of Living
Polar bears have long been assumed to have a relatively low metabolic rate, a big animal cruising slowly across the ice. Field measurements have upended that picture. Research tracking bears on spring sea ice found that their metabolic rates were about 1.6 times higher than previously estimated.5PubMed. High-energy, high-fat lifestyle challenges an Arctic apex predator, the polar bear Combined with low intake of fat-rich prey, more than half the bears in that study ended up in an energy deficit. They were burning through their reserves faster than they could replenish them.
Energy expenditure varies considerably between individual bears. When researchers tracked 20 bears on land, daily energy expenditure varied more than fivefold, with younger females spending the most energy per kilogram and adult males the least.6PubMed Central. Polar bear energetic and behavioral strategies on land with implications for surviving the ice-free period Pregnant females, meanwhile, had lower expenditure than non-pregnant females without cubs, consistent with conserving energy for the denning period ahead. This range matters because it shows that a successful hunting season is not guaranteed. Even in the best conditions, a significant fraction of bears may fail to catch enough seals to break even on their energy budget.
Moving on sea ice costs energy, too. Bears that moved to land from receding ice in summer spent about 22 percent more energy in August than bears that stayed on the retreating pack ice, partly because the transition involved substantially more swimming.7PubMed. The seasonal energetic landscape of an apex marine carnivore, the polar bear So even the decision of where to be has a significant energy cost.
How Cubs Learn the Craft
Polar bear cubs begin hunting while still with their mothers, and they show wide variation in patience and skill. In the same midsummer study that documented 288 hunts, all cubs present attempted to hunt, but some were far more persistent than others.8Canadian Journal of Zoology. Midsummer observations on the behavior of wild polar bears (Ursus maritimus) Yearling cubs and two-year-olds both spent less time hunting than adults, but two-year-olds showed a notable jump in proficiency. They performed still-hunts about twice as frequently as yearlings, and their kill rate was comparable to that of adults despite hunting for a smaller share of their time.9Canadian Journal of Zoology. Comparative hunting abilities of polar bear cubs of different ages
This suggests that the second year with the mother is when much of the real learning clicks into place. By that age, a cub has watched its mother through two full hunting seasons and has practiced the posture, the patience, and the timing of the strike. Researchers have noted that age-related increases in a female bear’s body weight track with improving hunting skills over her lifetime, meaning that even among adults, experience keeps paying dividends.10Journal of Zoology. Age‐specific reproductive performance of female polar bears (Ursus maritimus) A young bear fresh out of maternal care is a competent hunter, but an older one is probably a better one.
Opportunistic Prey Beyond Seals
Although ringed seals are the foundation of polar bear diets, these bears are opportunistic enough to take advantage of unusual prey when the chance arises. In the Canadian High Arctic, researchers documented bears preying on stranded belugas and narwhals. At one site on Somerset Island, four narwhals and two belugas were found dead on a beach, all attacked and partially consumed by polar bears.11Arctic. Predation of Belugas and Narwhals by Polar Bears in Nearshore Areas of the Canadian High Arctic These small whales sometimes become trapped in shallow water or stranded by shifting ice, creating a rare bonanza for any bear nearby.
Bears have also been observed diving after flightless geese during the birds’ summer molt, when they cannot fly. The energy math on this is tighter. Calculations suggest that dive-hunting geese can be worthwhile when the chase is short, under about 15 minutes, and especially when the bear is light or experienced. But the overall energy gain is modest compared to the bear’s full daily budget.12Arctic Science. Worth the dip? Polar bear predation on swimming flightless greater snow geese and estimation of energetic efficiency A goose is simply a small meal for a large predator. Spending an afternoon chasing geese is more of a snack break than a serious foraging strategy.
The Struggle to Hunt on Land
When sea ice retreats in summer, polar bears in some populations are forced ashore for weeks or months. The question of whether they can feed themselves on land has attracted intense research interest, and the answer so far is discouraging. Only small numbers of bears have been documented eating terrestrial foods in meaningful quantities. Body condition and survival rates have declined in areas where land use has increased, suggesting that time on land is time spent losing weight, not gaining it.13Frontiers in Ecology and the Environment. Can polar bears use terrestrial foods to offset lost ice‐based hunting opportunities?
Part of the problem is competition. Over much of the Arctic, the same terrestrial foods that bears might turn to, berries, grass, carrion, and bird eggs, already support brown bears, which are smaller and more efficient at extracting nutrition from low-quality plant material. A polar bear’s digestive system is optimized for marine mammal fat, not fibrous vegetation. Even raiding bird nests at scale is unlikely to close the gap. Modeling of nest predation by polar bears predicts that body condition will continue to decline even with increased egg consumption during ice-free periods.14PubMed. Increasing nest predation will be insufficient to maintain polar bear body condition in the face of sea ice loss A single egg is a tiny fraction of the calories in a seal pup.
Bears stranded on shore in the Southern Beaufort Sea have shown an interesting split. Those with access to bowhead whale carcasses from Indigenous subsistence harvests were able to scavenge enough to maintain their fat and protein stores. Those that followed the retreating ice far offshore beyond the continental shelf, where seal densities drop off, experienced genuine food deprivation, with blood markers indicating they were losing protein mass, not simply fasting in a controlled way.15PubMed. Phenotypic plasticity and climate change: can polar bears respond to longer Arctic summers with an adaptive fast? Roughly 70 percent of that subpopulation follows the ice rather than coming ashore, meaning most were going hungry.
Scavenging and the Grizzly Dynamic
Whale carcasses that wash ashore or are left after human harvests create a concentrated food source that draws bears from miles around. In northeastern Alaska, researchers observed both polar bears and grizzly bears competing for bowhead whale remains over multiple autumns. The competitive dynamic was not what you might expect from the larger species. Grizzly bears proved socially dominant, displacing polar bears from feeding sites more reliably than other polar bears did.16Journal of Mammalogy. Polar bear–grizzly bear interactions during the autumn open-water period in Alaska
The bears partitioned access to the resource by time of day. Lone adult polar bears and grizzlies fed mainly at night, while polar bear family groups and younger bears fed more during dawn and dusk. Mothers with cubs were the most aggressive polar bears in both same-species and cross-species encounters, a pattern consistent with protective maternal behavior. As grizzly bear ranges push northward with warming temperatures, these competitive interactions are likely to become more common, adding another pressure on polar bears already dealing with habitat loss.
Built for Ice and Fat
The polar bear’s body has been shaped by remarkably fast evolution. Their skulls are long, flat, and low-profiled with elevated eye sockets, a combination consistent with both a semi-aquatic lifestyle and a diet focused almost entirely on other animals. The rate of cranial shape change in the polar bear lineage was at least twice as fast as in any other bear lineage, with the modern skull form apparently established within a few hundred thousand years of their split from brown bears.17PubMed Central. Biomechanical Consequences of Rapid Evolution in the Polar Bear Lineage
Even their paw pads are specialized. Compared to brown bears and black bears, polar bear paw pads have papillae, the small bumps on the pad surface, that are about 1.5 times taller, giving the pads roughly 1.3 times more actual surface area. Friction experiments with 3D-printed model surfaces showed that these taller papillae increase grip on snow by a factor of 1.3 to 1.5.18PubMed Central. Polar bear paw pad surface roughness and its relevance to contact mechanics on snow Interestingly, because polar bear paws are proportionally smaller relative to body mass than those of other bears, the taller papillae may simply compensate for that size disadvantage, bringing total grip roughly in line with their relatives. It is a design tradeoff: smaller paws that swim better, with a grippier surface to make up for it on ice.
What Shrinking Ice Means for Hunting
Everything about polar bear hunting depends on sea ice. The breathing holes, the hauled-out seals, the stable platform for patient still-hunting: all of it requires ice. Projections for Western Hudson Bay, one of the best-studied polar bear regions, suggest that spring ice concentration will remain high through about 2050 under most climate scenarios, but under moderate to high emissions pathways, ice drops steeply in the second half of the century. Under the highest emissions scenario modeled, spring ice concentration by the 2090s falls to about 20 percent, down from above 90 percent today.19PubMed. Future sea ice conditions in Western Hudson Bay and consequences for polar bears in the 21st century The researchers concluded that the population may struggle to persist past mid-century under moderate to high warming.
Higher metabolic rates than previously assumed make this picture worse. If bears need 1.6 times more energy than earlier models estimated, and the ice season during which they can hunt seals efficiently is shrinking, the window for building up fat reserves gets both shorter and harder to exploit.20PubMed. High-energy, high-fat lifestyle challenges an Arctic apex predator, the polar bear More fragmented ice also means more swimming and more walking between hunting sites, burning calories that the bear may not be able to replace.
Contaminants Moving Through the Food Chain
Polar bears sit at the top of the Arctic marine food web, and that position comes with a chemical cost. Persistent organic pollutants, including PCBs and pesticide residues, accumulate in marine organisms and concentrate as they move up the food chain. Measurements from northern Alaska found that polar bears carried PCB concentrations roughly four to five times higher than those in their primary prey, ringed seals. Organochlorine levels in bears near Barrow, Alaska, were lower than in bears from the Canadian Arctic, which researchers attributed partly to the Barrow bears also feeding on lower-trophic-level prey like bowhead whale carcasses, which carry lighter pollutant loads than seals.21PubMed Central. Persistent organochlorine pollutants in ringed seals and polar bears collected from northern Alaska
This finding connects back to the scavenging behavior observed near coastal communities. Bears that eat whale remains are not just getting a caloric supplement; they are also, inadvertently, ingesting a somewhat different contaminant profile than strictly seal-dependent bears. As ice loss pushes more bears toward shore and toward opportunistic terrestrial and whale-scavenging diets, the contaminant dynamics for different subpopulations may shift in ways that are difficult to predict but worth monitoring.