The polar bear (Ursus maritimus) is the world's largest land carnivore, native to the Arctic sea ice across five countries: Canada, the United States (Alaska), Russia, Norway (Svalbard), and Greenland (Denmark). Adults are highly specialized for life on sea ice, with water-repellent fur, partially webbed feet, and a metabolism that can shift dramatically depending on food availability. They are classified as Vulnerable on the IUCN Red List, with the global population estimated at 20,000 to 31,000 individuals as of the most recent IUCN assessment.
Polar bears sit at the top of the Arctic marine food web, feeding primarily on ringed seals (Pusa hispida) and bearded seals (Erignathus barbatus), which they hunt from the surface of sea ice. The accelerating loss of Arctic sea ice driven by climate change is the single greatest long-term threat to the species, reducing the time bears can spend hunting and forcing longer fasting periods on land. Secondary pressures include industrial development in the Arctic, shipping traffic through previously frozen routes, and the bioaccumulation of persistent organic pollutants, which concentrate in the fat that bears depend on for survival.
Polar bears communicate through low chuffs, growls, and hisses rather than loud roars. Mothers use soft chuffing calls to reassure cubs, while males competing for mates during the spring breeding season on the sea ice of the Beaufort and Chukchi seas produce deeper, more aggressive vocalizations.
Adult male polar bears typically measure 7.9 to 9.8 feet from nose to tail, making them the largest land carnivores on Earth alongside Kodiak brown bears. Females are considerably smaller, usually ranging from 5.9 to 7.9 feet in length.
Adult male polar bears typically weigh between 775 and 1,300 pounds, while females weigh roughly half that, between 330 and 650 pounds. A bear's weight can vary dramatically across the year, as they accumulate thick fat reserves after hunting ringed seals on Arctic sea ice.
Polar bears prey primarily on ringed seals and, to a lesser extent, bearded seals, ambushing them at breathing holes and ice edges across the Arctic. As sea ice loss reduces hunting access, bears increasingly face longer fasting periods and are turning to lower-calorie land-based foods like bird eggs.
Polar bears can run at bursts of up to 25 miles per hour on land or sea ice, though they overheat quickly at that pace. They are far more energy-efficient as swimmers, covering long distances at around 6 miles per hour through frigid Arctic waters.
A polar bear standing upright on its hind legs can reach 10 feet tall, and an adult male at all fours typically stands around 4 to 5 feet at the shoulder. According to the IUCN Red List, this Vulnerable species depends on stable sea ice habitat that is shrinking with rising Arctic temperatures.
