Porpoise

The porpoises are small cetaceans of the family Phocoenidae; they are related to whales and dolphins.

They are, however distinct from dolphins, although the word "porpoise" is often used to refer to any small dolphin, especially in North America. A key difference is the shape of the teeth, which in dolphins are conical, whereas porpoises have spade-shaped teeth.

Porpoises tend to be smaller but stouter than dolphins. They have small, rounded heads and no beaks. In addition, a porpoise's dorsal fin is generally triangular, rather than curved like that of many dolphins.

Porpoises tend to be less acrobatic and more wary than dolphins; several species are under threat from man's activities.

Taxonomy

• ORDER CETACEA
  • Suborder Mysticeti
    • Family Eschrichtiidae: Gray Whale
    • Family Balaenopteridae: rorquals
    • Family Balaenidae right whales
    • Family Neobalaenidae: Pygmy Right Whale
  • Suborder Odontoceti
    • Family Platanistoidea: river dolphins
    • Family Delphinidae: oceanic dolphins
    • Family Phocoenidae
      • Vaquita, Phocaena sinus
      • Finless Porpoise, Neophocaena phocaenoides
      • Harbour Porpoise, Phocaena phocaena
      • Burmeister's Porpoise, Phocaena spinipinnis
      • Spectacled Porpoise, Phocaena dioptrica
      • Dall's Porpoise, Phocoenoides dalli
    • Family Monodontidae: Beluga and Narwhal
    • Family Physeteridae: Sperm Whale
    • Family Kogiidae: Pygmy Sperm Whale and Dwarf Sperm Whale
    • Family Ziphiidae: beaked whales