Dolphins are marine mammals that are closely related to whales and
porpoises. There are almost forty species of dolphin in seventeen genera.
They vary in size from 1.2 m (4 ft) and 40 kg (90 lb) (Maui's Dolphin), up
to 9.5 m (30 ft) and 10 tonnes (9.8 LT; 11 ST) (the Orca or Killer Whale).
They are found worldwide, mostly in the shallower seas of the continental
shelves, and are carnivores, mostly eating fish and squid. The family
Delphinidae is the largest in the Cetacea, and relatively recent: dolphins
evolved about ten million years ago, during the Miocene. Dolphins are
considered to be amongst the most intelligent of animals and their often
friendly appearance and seemingly playful attitude have made them popular in
human culture.. - source www.wikipedia.org
