✔ 最佳答案
Dolphins are aquatic 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 (88 lb) (Maui's Dolphin), up to 9.5 m (30 ft) and ten tonnes (the Orca). 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.