Order: Carnivora (Ursidae, Mustelidae, Otariidae, Phocidae, Odobenidae)


There are five families of marine mammals within the Order Carnivora that can be divided into two groups: pinnipeds (“flipper-footed”) and fissipeds (“pad- or paw-footed”). Pinnipeds are seals, sea lions and walruses; fissipeds are polar bears and otters.

The two fissiped families are:

  • Ursidae
    • Polar bear
    • the only bear considered a marine mammal
    • their overwhelming dependence on the ocean for their food is the reason they are classified a marine mammal
    • by being designated a marine mammal, the polar bear is covered by marine mammal protection laws
    • found in Arctic regions of Canada and Alaska
  • Mustelidae
    • sea otters, river otters, weasels, badgers
    • otters are the smallest marine mammal
    • river otters are smaller than sea otters
    • they do not live in the water permanently, rather they live mostly along shorelines near sea kelp which provides an ideal environment for their hunting and hiding from other predators
    • bodies are completely covered in fur
    • no flippers, but four feet that propel them in the water with the aide of a long tail
    • feet are not good for swimming, but are nimble enough to use rocks as tools in order to break apart shellfish for eating
    • otters are found in the coastal waters of the northern Pacific from California to Canada and over to Alaska and Russia
    • examples: sea otter, marine otter, river otter

The three pinniped families in Order Carnivora are:

  • Otariidae
    • sea lions and fur seals
    • visible ears
    • can walk on all four flippers (rotates hind flippers forward under the body)
    • more mobile on land than true seals
    • most of swimming power generated by front flippers that are large
    • example: California sea lion, Guadalupe fur seal, Stellar sea lion, northern fur seal
  • Phocidae
    • true seals
    • no external ears (hint: true seals have their heads “sealed” shut with no ears visible, much like a spectator cannot see the quarterback’s ears under his helmet)
    • more mobile in water than on land
    • smaller front flippers limit ability to walk on land
    • hind flippers do not rotate under the body, further limiting walking on dry land
    • large, fan-like rear flippers are not good for walking, but in the water are the main source of thrust
    • example: Pacific harbor seal, northern elephant seal
  • Odobenidae
    • walrus
    • two distinctive tusks descent from mouth
    • inhabits Arctic waters and ice floes
    • no external ears
    • better at walk on land than seals
    • like sea lions, walruses can rotate their hind flippers under their body to help walk on land
    • two main things differentiate the walrus from other pinnipeds:
      • two distinctive tusks
      • two large air sacs on either side of their larynx within their throat are used to inflate and keep the head afloat when sleeping and when submerged the air pouches act as resonance chambers to help amplify their underwater sounds




  • African Clawless Otter (Aonyx capensis)
  • Asian Small-Clawed Otter (Aonyx cinereus)
  • Congo Clawless Otter (Aonyx congicus)
  • Eurasian Otter (Lutra lutra)
  • Giant Otter (Pteronura brasiliensis)
  • Hairy-Nosed Otter (Lutra sumatrana)
  • Marine Otter (Lontra felina)
  • Neotropical Otter (Lontra longicaudis)
  • North American River Otter (Lontra canadensis)
  • Sea Otter (Enhydra lutris)
  • Smooth-Coated Otter (Lutrogale perspicillata)
  • South American River Otter (Lontra provocax)
  • Spotted-Necked Otter (Hydrictis maculicollis)