Katmai's Mammals

Scientists in Katmai have documented 42 species of mammals from the coast to the tundra. Brown bears and moose live throughout the coastal and lake regions of Katmai National Park and Preserve. Other mammals include caribou, red fox, wolf, lynx, wolverine, river otter, mink, marten, weasel, porcupine, snowshoe hare, red squirrel, and beaver. Along the coast are sea lions, sea otters, harbor seals, porpoise. Beluga whales, orcas, and gray whales sometimes use the Shelikof Strait just beyond Katmai's boundaries.

One of the largest land mammals in North America to some of the smallest, Katmai has many species that thrive here.

Brown bear submerged in water
The brown bears at Brooks Camp in Katmai show excellent swimming skills by diving and snorkeling to fish for salmon.

Brown Bear (Ursus arctos)
Explore the National Park Service’s bear page to learn about bears, the work we do to protect them, and guidelines for staying safe around them.

  • Brown bears can live to be about 20 years old on average, but the oldest brown bear was about 35 years old.
  • They can stand 3-5 feet (.9-1.5 m) at the shoulder and measure 7-10 feet (2.1-3 m) in length.
  • Adult males can weigh 600-900 pounds (272-408 kg) and by the end of the fall over 1000 pounds (454 kg). Adult females average about 1/3 less.
  • Females can have between 1-4 cubs, and the cubs stay with mom on average 2-3 years.

Find out more on Katmai’s bears in the brown bear frequently asked questions.

Grey wolf along coast
Their ability to travel long distances makes wolves good hunters.

Gray Wolf (Canis lupus)
Little is known about Katmai’s wolf population. Wolves have been seen throughout the park; along the coast hunting sea otter and harbors seals, and in Brooks Camp fishing alongside bears.

  • Wolves on average can live up to 12 years old in the wild.
  • They can be 2.5 feet (.8 m) tall at the shoulders.
  • The average male weighs 105 pounds (48 kg) and the average female weighs 88 pounds (40 kg).
  • Wolf packs usually include dominant male and female breeding pairs, their offspring, and other non-breeding adults.
  • Wolf packs usually live within a specific territory and may travel within that territory as far as 30 miles (48 km).
Learn more about wolves in Alaska by exploring Denali National Park and Yukon-Charley Rivers National Preserve.

sea otter and pup in water
A female sea otter's pregnancy can be 5-8 months, and the new pup will depend on their mothers for 5-12 months on average.

Sea Otter (Enhydra lutris)
Sea otters are a keystone species to Katmai’s coastal environments.

  • Sea otters on average live between 10-15 years for males, and 15-20 years old for females.
  • The average length for sea otters is 4-5 feet (1-1.5 m), but can grow to be 6 feet (1.8) long. The can weigh up to 80-100 pounds (36-45 kg).
  • Instead of blubber or a large size to stay warm, sea otters have a thick coat of fur with dense underfur.
  • Sea otters typically give birth to one pup, but can give birth to twins.
  • Sea otter pups can be born at any time of the year, but usually in early summer, and weigh about 5 pounds (2.3 kg). These pups need constant attention since they can’t swim, feed or clean themselves.
The Southwest Alaska Network monitors sea otters along Katmai’s and Kenai Fjords’ coast.

Humpback whale tail out of water
Feeding almost 23 hours a day, a humpback whale can consume almost a half ton (454 kg) of food.

Humpback Whale (Megaptera novaeangliae)
Humpback whales can be seen in the Shelikof Strait along Katmai’s coast.

  • Humpback whales can live to be in their sixties on average, but the oldest known humpback lived to be 96.
  • Male humpbacks can average to be 46 feet (13 m) long and weigh 25 tons (22,680 kg). Females can average to be 49 feet (15 m) long and weigh 35 tons (31,752 kg).
  • Their pectoral fins (flippers) are nearly one-third of their total body length. The dorsal fin shape varies, but is often noticeable when the whale arches its back to dive.
  • Many humpbacks spend their winters around Hawaii and Mexico (breeding grounds) and their summers in Alaska (summer feeding grounds).
  • Female humpbacks can occasionally give birth to twins, but typically one is normal. At birth the calf is 16 feet (5 m) long and weighs 2 tons (1,814 kg).
Explore Kenai Fjords National Park and Glacier Bay National Park to learn more about humpback whales.

Last updated: June 1, 2021

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