Although scientists believe that land animals evolved from sea animals, dolphins are some of the very few sea animals that evolved from land animals. About 60 million years ago, the dolphin ancestor Mesonychid condolarth, a wolflike creature with hooves, lived on land. Dolphins swim in. . . Although dolphins can be found in all the oceans, some dolphin species live only in certain parts of the world. Dusky dolphins, for example, are found south of the Equator, only near New Zealand, Peru, and Argentina.
Dolphins spend their time in small groups of five to seven individuals.
The groups come together to play, feed and find mates, then separate. Dolphins often rejoin a group later, often with different family members or friends. This pattern of behavior is called. . . Fission means separating and fusion means joining. Dolphins behave this way throughout their entire lives.