--- title: "Polar Bear (Ursus maritimus) | AnimalTracks.wiki" description: "Arctic apex predator with hollow, see-through fur over jet-black skin, a nose that smells seals 20 miles off, and a shrinking sea of ice to swim." image: "https://animaltracks.wiki/images/animals/polar-bear-1.webp" published: "2026-09-01" updated: "2026-09-23" --- # Polar Bear (*Ursus maritimus*) > **Status**: Checked against 7 sources, listed under Sources below. > **Tagline**: Arctic apex predator with hollow, see-through fur over jet-black skin, a nose that smells seals 20 miles off, and a shrinking sea of ice to swim. > **Soundtrack Vibe**: Blackgaze & Atmospheric Post-Metal // Chelsea Wolfe, "Seethe" > **Soundtrack Links**: [Spotify](https://open.spotify.com/track/4eYfOnJz3APqGzWPwWtC5r) > **Vibe Match**: Doom that simmers for minutes before it breaks, for a bear that can remain motionless for hours above a seal's breathing hole, waiting for a seal to pop up. ## Biological Superpowers & Stats - **Taxonomy**: *Ursus maritimus* - **Danger Level**: Deadly - **Conservation Status**: Vulnerable ([IUCN Red List](https://www.iucnredlist.org/)) - **Superpower**: Jet-black skin under hollow, clear guard hairs, with up to 10 centimeters (4 inches) of fat beneath it. - **Habitat**: Circumpolar Arctic sea ice packs, coastal leads, and frozen Arctic Ocean bays - **Diet**: Mainly ringed and bearded seals, plus walruses, belugas, and scavenged whale carcasses - **Tags**: bear, ocean, arctic-tundra, apex-predator, solitary-hunter, pack-ice ## Natural History & Behavior ## Built Big A polar bear (*Ursus maritimus*) is, most experts agree, the longest of the world's eight bear species, and San Diego Zoo Wildlife Alliance reports that males can stand over 12 feet (3.7 meters) on their hind legs. Typical adult males weigh 300 to 635 kilograms (660 to 1,400 pounds); one enormous bear on record weighed more than 770 kilograms (1,700 pounds). Females run smaller, at 150 to 250 kilograms (330 to 550 pounds), though a pregnant female can weigh more than 453 kilograms (1,000 pounds) before she dens for winter. Alongside the brown bear, it's one of the two largest carnivores that live on land. Wild polar bears are estimated to live 25 to 30 years; Animal Diversity Web's oldest captive record, a female at the Detroit Zoo, reached 43 years and 10 months. ## A Nose Built for a White World Polar bears have two ways to hunt, and still-hunting is the one they use most: waiting motionless for hours beside a seal's breathing hole in the ice until it surfaces. San Diego Zoo Wildlife Alliance says a polar bear's nose can pick up a seal's scent from 20 miles (32 kilometers) away, sniff out a seal's den under the snow, and find a breathing hole in the ice up to a mile (1.6 kilometers) away. Moving around is expensive: the zoo notes it costs a polar bear about twice the energy of most mammals, which helps explain why it prefers to sit and wait rather than chase. A study that measured the metabolic rates of nine wild bears found their energy use ran 1.6 times higher than scientists had assumed, leaving more than half the bears studied in an energy deficit. ## The Fiber-Optic Myth > **Zero white pigment** Each guard hair is a hollow, clear tube, and what looks like white fur is really light refracting off that structure over jet-black skin underneath. That much is real biology. What doesn't survive testing is the popular add-on that those hollow hairs work like fiber-optic cables that guide ultraviolet light. A 1998 study in Applied Optics measured how fast light fades inside real polar bear hairs, 2 to 8 decibels per millimeter, a loss rate that, with a reanalysis of older data, its author says seems to rule the idea out. Underneath the coat sits a layer of fat 5 to 10 centimeters (2 to 4 inches) thick. It is backup energy when food is scarce, and it may also help insulate the bear and keep it afloat. ## Swimming a Sea That Keeps Shrinking Polar bears are excellent swimmers, paddling with their broad front feet and steering with their back legs like rudders. San Diego Zoo Wildlife Alliance says they have been known to swim more than 100 kilometers (60 miles) without resting. In the southern Beaufort and Chukchi seas, a study that GPS-tracked 52 adult females over six years logged 50 long-distance swims by 20 bears, averaging 154 kilometers and reaching as far as 687 kilometers, some lasting up to 9.7 days. The researchers suggest the swims are a response to shrinking summer sea ice. The U.S. Fish and Wildlife Service puts the global population at about 26,000 bears as of 2023, spread across 19 subpopulations. The IUCN lists the species as Vulnerable. San Diego Zoo Wildlife Alliance notes that disappearing sea ice is linked to declines in polar bears' body condition, reproduction and survival. ## Frequently Asked Questions ### Do polar bear hairs really work like fiber-optic cables? No. A 1998 study in Applied Optics measured how much light a polar bear hair loses over distance: 2 to 8 decibels per millimeter in visible light. That loss rate, together with a reanalysis of older data, seems to rule out the idea that the hairs guide ultraviolet light like fiber-optic cables. What's true is simpler: the fur has zero white pigment, each hair is a hollow, clear tube, and underneath it all is jet-black skin. *(Source: [Koon 1998]())* ### Why do polar bears hunt by waiting instead of chasing seals? Because moving is expensive. San Diego Zoo Wildlife Alliance says it costs a polar bear about twice as much energy to get around the Arctic as it does most other mammals, which helps explain why polar bears prefer sit-and-wait hunting to chasing. They wait motionless for hours beside a seal's breathing hole until it surfaces, then strike. *(Source: [San Diego Zoo Wildlife Alliance]())* ### Why are polar bears classified as marine mammals? The U.S. Fish & Wildlife Service classifies the polar bear as a marine mammal, protected under the Marine Mammal Protection Act. Its scientific name, Ursus maritimus, means sea bear, and it depends largely on sea ice. *(Source: [U.S. Fish & Wildlife Service]())* ## Sources 1. [Polar Bear. San Diego Zoo Wildlife Alliance.]() 2. [Polar Bears: Icons of the Arctic. San Diego Zoo Wildlife Alliance.]() 3. [Ursus maritimus (polar bear). Animal Diversity Web, University of Michigan.]() 4. [Polar Bear (Ursus maritimus). U.S. Fish & Wildlife Service.]() 5. [Koon (1998). Is polar bear hair fiber optic? Applied Optics.]() 6. [Pagano et al. (2018). High-energy, high-fat lifestyle challenges an Arctic apex predator, the polar bear. Science.]() 7. [Pagano et al. (2012). Long-distance swimming by polar bears (Ursus maritimus) of the southern Beaufort Sea during years of extensive open water. Canadian Journal of Zoology.]() *Published September 1, 2026. 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