Polar bears, whose scientific name Ursus maritimus means “sea bear,” are deeply connected to the Arctic’s icy environment. They rely on sea ice for hunting seals and navigating their vast habitat. Their specialized adaptations allow them to thrive in this extreme climate.
Polar Bear Swimming Capabilities
Polar bears possess remarkable aquatic abilities, regularly undertaking swims exceeding 30 miles (48 kilometers). Studies using GPS collars on adult female bears documented numerous long-distance swims, averaging 96 miles (154 kilometers) over 3.4 days.
A notable record includes a female polar bear swimming 426 miles (686 kilometers) continuously over nine days. Polar bears can maintain speeds of up to 6.2 miles per hour (10 kilometers per hour) and are capable of swimming for several hours without rest, covering distances of 62 miles (100 kilometers) or more.
Reasons for Extensive Swimming
Polar bears traditionally swim to move between ice floes, pursue seals, or reach land. However, recent decades show a significant change in their swimming patterns. The reduction and earlier melt of Arctic sea ice, driven by climate change, compel polar bears to undertake longer, more frequent swims.
As sea ice retreats farther from shore, bears must traverse vast expanses of open water to locate stable ice for hunting, finding mates, or accessing terrestrial habitats. Their reliance on sea ice as a hunting ground means disappearing ice directly impacts their ability to secure food, making these extended swims a necessity for survival.
How Polar Bears Are Adapted for Swimming
Polar bears exhibit specific physical traits that make them adept swimmers. Their large, slightly webbed front paws function like powerful paddles, propelling them in a doggy-paddle style. Hind legs and feet act as rudders, providing steering and stability.
A thick layer of blubber, up to 4.5 inches (11 centimeters) thick, provides insulation and buoyancy. Their fur, with hollow hairs, also contributes to buoyancy and insulation by trapping air. Additionally, polar bears can close their nostrils and hold their breath for about two minutes, with a documented record of three minutes and ten seconds.
Survival Implications of Extended Swims
While polar bears are capable swimmers, these increasingly long journeys carry substantial risks. Swimming consumes three to five times more energy than walking for the same distance. This high energy expenditure can lead to severe exhaustion and considerable loss of body mass, with one documented case showing a 22 percent body weight reduction after a nine-day swim.
Cubs are particularly vulnerable during prolonged swims due to their smaller size and limited fat reserves, making them susceptible to hypothermia and fatigue. Studies show a 45 percent mortality rate for cubs accompanying mothers on swims exceeding 30 miles, compared to 18 percent for cubs not undertaking such journeys. The open water environment also offers fewer hunting opportunities, compounding energetic demands and threatening their health and population stability.