Diet
Dolphins consume a variety of prey including fish, squid and crustaceans.
Population
It is difficult to estimate population numbers since there are many different species spanning a large geographic area.
Range
Most species live in shallow areas of tropical and temperate oceans throughout the world. Five species live in the world 's rivers.
Behavior
Dolphins are well known for their agility and playful behavior, making them a favorite of wildlife watchers. Many species will leap out of the water, spy-hop (rise vertically out of the water to view their surroundings) and follow ships, often synchronizing their movements with one another. Scientists believe that dolphins conserve energy by swimming alongside ships, a practice known as bow-riding.
Dolphins live in social groups of five to several hundred. They use echolocation to find prey and often hunt together by surrounding a school of fish, trapping them and taking turns swimming through the school and catching fish. Dolphins will also follow seabirds, other whales and fishing boats to feed opportunistically on the fish they scare up or discard. Reproduction
Mating Season Throughout the year, though in some areas there is a peak in spring and fall.
Gestation 9-17 months depending on the species. When it is time to give birth, the female will distance herself from the pod, often going near the surface of the water.
Number of offspring Usually one calf; twins are rare.
As soon as the calf is born, the mother must quickly
References: Baiji (or Chinese river dolphin), Lipotes vexillifer (possibly extinct, since December 2006) Family Pontoporiidae