Chordata · chordates

Risso's dolphin

Grampus griseus

Delphinidae · oceanic dolphinsIUCN: Least Concern
Risso's dolphin
Photo: AliceMartinelli8 · CC BY-SA 4.0 · Wikimedia Commons · resized

A blunt-headed dolphin covered in white scars from squid and other Risso's.

Fun factIts scars build up over its life until older adults look almost white.

Waters
Worldwide, Northeast US
Depth zone
Open-ocean surface waters
Diet
Squid
Size
Up to 4 m

Classification

Chordata › Mammalia › Artiodactyla › Delphinidae

  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 Artiodactyla even-toed hoofed mammals (whales included)
    • Even-toed hoofed mammals (cows, deer, hippos) and their relatives the whales
    • Whales evolved from land ancestors close to hippos
  13. Infraorder Cetacea whales, dolphins & porpoises
    • Whales, dolphins, and porpoises: fully aquatic, with flippers and a horizontal tail fluke
    • Breathe through a blowhole on top of the head
    • Thick blubber instead of fur
  14. Parvorder Odontoceti toothed whales
    • Toothed whales: teeth instead of baleen
    • One blowhole
    • Find prey by echolocation using a fatty 'melon' in the forehead
  15. Family Delphinidae oceanic dolphins
    • Oceanic dolphins: most have a beak and a curved dorsal fin
    • Includes orcas and pilot whales
  16. Genus Grampus
    • Species in the same genus are very close relatives and often look alike.
  17. Species Grampus griseus Risso's dolphin

Closest relatives in the guide