Chordata · chordates

Weddell seal

Leptonychotes weddellii

Phocidae · true sealsIUCN: Least Concern
Weddell seal
Photo: Andrew Shiva / Wikipedia · CC BY-SA 4.0 · Wikimedia Commons · resized

The most southerly breeding mammal, living under Antarctic fast ice.

Fun factIt keeps breathing holes open by scraping the ice with its teeth.

Waters
Southern Ocean
Depth zone
Coastal shallows & estuaries
Diet
Toothfish & fish
Size
Up to 3 m

Classification

Chordata › Mammalia › Carnivora › Phocidae

  1. Kingdom Animalia animals
    • Many-celled organisms that eat other living things for energy (heterotrophs)
    • Cells have no cell walls
    • Most can move at some stage of life
  2. Clade Bilateria bilateral animals
    • Body has a left and right side that mirror each other (bilateral symmetry)
    • Head end with concentrated nerves; three tissue layers
    • Includes about 99% of all living animal species
  3. Clade Deuterostomia deuterostomes
    • In the embryo, the first opening becomes the anus and the mouth forms second
    • Includes echinoderms and chordates
  4. Phylum Chordata chordates
    • At some stage of life: a stiffening rod along the back (notochord)
    • A hollow nerve cord along the back (dorsal)
    • Slits in the throat (pharyngeal slits) and a tail past the anus
  5. Subphylum Vertebrata vertebrates
    • A skull (cranium) protecting a brain
    • Backbone or similar support around the nerve cord
    • Includes fishes, amphibians, reptiles, birds, and mammals
  6. Infraphylum Gnathostomata jawed vertebrates
    • Jawed vertebrates: jaws formed from gill arches
    • Paired fins or limbs
    • Includes all fishes except hagfish and lampreys, plus all tetrapods
  7. Superclass Osteichthyes bony vertebrates
    • Bony vertebrates: skeleton made largely of bone
    • Most have a lung or swim bladder
    • Includes ray-finned and lobe-finned fishes and all tetrapods
  8. Clade Sarcopterygii lobe-finned vertebrates
    • Lobe-finned: fleshy fins with bones like those of limbs
    • Includes coelacanths, lungfishes, and all tetrapods
  9. Clade Tetrapoda four-limbed vertebrates
    • Four limbs with fingers and toes (or descended from animals that had them)
    • Breathe air with lungs
  10. Class Mammalia mammals
    • Mammals: hair at some stage of life
    • Females nurse their young with milk (mammary glands)
    • Three small bones in the middle ear
  11. Superorder Laurasiatheria whales, carnivorans & kin
    • Large group of placental mammals including whales, carnivores, bats, and hoofed animals
  12. Order Carnivora carnivorans
    • Carnivorans: sharp cheek teeth for shearing meat (carnassials) in most
    • Includes cats, dogs, bears, seals, and weasels
  13. Suborder Caniformia dog-like carnivorans
    • Dog-like carnivorans: dogs, bears, weasels, and seals
  14. Clade Pinnipedia seals, sea lions & walrus
    • Seals, sea lions, and walruses: limbs shaped into flippers
    • Insulating blubber; come ashore or onto ice to breed
  15. Family Phocidae true seals
    • True seals: no external ear flaps
    • Swim with their back flippers and wriggle on land
  16. Genus Leptonychotes
    • Species in the same genus are very close relatives and often look alike.
  17. Species Leptonychotes weddellii Weddell seal

Closest relatives in the guide