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Polar Bear (Ursus maritimus) Fact Sheet: Diet & Feeding


Highly carnivorous diet

  • Marine mammals (e.g., Stirling and Archibald 1977; Iversen et al. 2013; McKinney et al. 2013; Galicia et al. 2015; Galicia et al. 2016; McKinney et al. 2017; Laidre et al. 2018a; Smith and Stirling 2019; Florko et al. 2021; Michaux et al. 2021)
    • Primarily eat ringed seals, Pusa hispida
      • Greater than 50% of the prey base in most Arctic regions (Thiemann et al. 2008)
    • Also harp seals, hooded seals, bearded seals, and harbor seals
    • Occasionally: walruses, beluga whales, and narwhals
      • Viscount Melville Sound: beluga makes up about 20% of diet (Florko et al. 2021)
        • Highest consumption reported of any subpopulation
    • Polar bears are adapted to eat soft, high-calorie blubber (also, flesh but often leave meat for scavengers)
      • Primarily carnivorous, compared to brown and black bears (Rinker et al. 2019)
      • Diet constrained by skull morphology and dentition (Slater et al. 2010; Petherick et al. 2021)
        • Skull and teeth not well adapted for processing bone and tough plant foods
          • Smaller grinding surfaces on molars compared to brown bears
      • McKinney et al. (2013) noted polar bear's diet can shift to include more subarctic seal species with warmer temperatures and less sea ice [Greenland]
      • In recent years, observations of polar bears in Alaska broadening somewhat diet to include harder foods (Petherick et al. 2021)
        • Foraging on seal carcasses, at bowhead bone piles (discards of native subsistence hunting), and from human trash
  • Birds and their eggs
    • Geese, eider, and other seabirds and waterfowl (Stempniewicz 2006; Prop et al. 2013, 2015; Rode et al. 2015; Laidre et al. 2018a; Barnas et al. 2020)
  • Less common prey
    • In summer, if preferred food is unavailable, take land plants and lichen, seaweed/kelp, berries, small mammals, birds, and egg ((Lønø 1970; Iversen et al. 2013; Laidre et al. 2018a)
    • Opportunistically feed on whale carcasses caught by native subsistence hunters (Rogers et al. 2015; Atwood et al. 2016; Galicia et al. 2016; Pongracz et al. 2017b; Wilson et al. 2017; Bourque et al. 2020; Pagano et al. 2020; Florko et al. 2021; Griffen et al. 2022) and killer whale predation (Galicia et al. 2016)
      • E.g., bowhead whale remains in Northern and Southern Beaufort Sea, and Foxe Basin, Canada
    • In Svalbard, Norway, have been observed hunting reindeer (Iversen et al. 2013; see Stempniewicz et al. 2021)
      • One hunting event involved a polar bear chasing and overtaking a reindeer in water
    • Observed feeding on white-beaked dolphins trapped by ice floes (Aars et al. 2015)
    • In Canada, polar bears observed:
      • Infrequently scavenging on remains of land mammals and birds (Michaux et al. 2021)
      • Hunting caribou on the coast of Hudson Bay (Brook and Richardson 2002)
      • Fishing Arctic charr and fourhorn sculpin in Nunavut (Dyck and Romberg 2007)

Energy needs under harsh conditions

  • High energy (metabolic) needs (Pagano et al. 2018b)
  • Consume large amounts of fat when food is available
    • Gain majority of their body fat in the late spring and early summer
    • 90% of the energy eaten is assimilated directly to fat stores (Best 1977)
    • Metabolize fat when there is nothing to eat
  • Can endure long periods without feeding (e.g., Pilfold et al. 2016)
  • Often kill more than they can eat
    • Rarely cache food, unlike other bears
    • Large stomach can hold more than 70 kg (154 lb) of food
  • Eating fat adds water to their diet
    • Water released when fat is digested (metabolized)


  • Vitamin A content of liver ranges between 15,000 and 30,000 units per gram.
    • Phosphate, lipid and cholesterol contents relatively low.
  • Bear milk is high in fat and protein but low in carbohydrates.
    • Polar Bears have richest milk of all bears
    • 35.8% milk fat when emerge from dens - 20.6% fat with yearlings
    • Sodium content is higher than that of other milks.



  • Use sit-and-wait tactics to hunt seals (e.g., Stirling 1974; Pagano et al. 2018b)
    • Stalk prey less often
  • Locate birth lairs and breathing holes of Ringed Seals by smell and sound
    • Approach slowly to minimize their own sound
    • May break into lair immediately, or wait motionless and listening for several hours for seal to return
    • Walk cross current to winds to pick up smell (Togunov et al. 2017)
  • Swim underwater to stalk seals lying at the edge of an ice floe
  • Consume fat first
    • Tissue with most calories prioritized
  • Prey selection may differ somewhat between male and female polar bears (Galicia et al. 2015)
    • Large adult males may be better able to hunt larger prey (e.g., large seals, beluga, etc.)
  • Considerable competition between Polar Bears for a kill; larger bears will run off smaller bears
  • Small size of prey probably eliminates any advantage in group hunting
    • But bears may scavenge together at a whale carcass or human garbage dump
  • Wash and lick themselves while feeding; spend up to 15 minutes grooming afterward


  • Subadults may scavenge kills left by larger individuals (e.g., Stirling 1974; Pilfold et al. 2014)
    • Scavenge more commonly than adults, which are more adept and experienced hunters
  • Provides limited opportunity for weight gain/maintenance (Pagano et al. 2018b)

Food caching

(Stirling et al. 2020; Stempniewicz et al. 2021)

  • After eating prey's fat and other high-value tissues, may bury carcass under snow, grass, or dirt
    • Conceals remains from scavengers
  • Short-term; generally cache for only a few days
  • Observed in Svalbard, Greenland, and Canada
    • But generally, an uncommon behavior
      • Fewer scavengers on sea ice than land; behavior may benefit polar bears less than other bear species


  • Thought to occur infrequently (Stirling and Ross 2011)
  • Bears at risk are mainly cubs, but sometimes also adult females (Stirling and Ross 2011)
    • May be killed in a similar manner to how polar bears hunt seals (bites behind the head)
  • Possible motivations (see refs in Stirling and Ross 2011; Ivanov et al. 2020)
    • Hunger
    • To avoid competition
    • For males, to increase breeding opportunities (infanticide)
  • Most kills known to occur on land (Stirling and Ross 2011; Ivanov et al. 2020)

Tool use

(Stirling et al. 2021)

  • Suspected for a small number of individuals
  • Use rocks or ice to hunt seals and (rarely) walrus

Page Citations

Amstrup (2003)
Demaster & Stirling (1981)
Derocher et al (1993)
Derocher et al (2004)
Stirling (1993)

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