Dolphins are marine mammals which inhabit almost all the oceans in the world and few rivers as well. These are human friendly and are part of many a proud collection displayed in many aquariums in order to entertain us. There are approximately 24 species of dolphins in the world. They can survive alone, but thrive in groups, which are known as pods. The group living is used to hunt and feed on preys. The migration pattern of wild dolphins is dependent on their food source.

They live in temperate waters and feed on variety of fish, such as herring, squids, Pacific sardines, anchovies, capelin, hake, salmon, cod, mackerel and rock-fish. Some of the species of dolphins also eat bigger prey, such as sea lions, seals and turtles. Although dolphins migrate mainly in search of food, warm water surface temperatures of 10 to 20 degrees Celsius, and in order to avoid certain predators, the pattern of migration is not specific and repetitive.

In the areas inhabited by dolphins with shallow water, the variation in temperatures right round the year is rather considerable. The surrounding air temperature also varies independent of the water temperature. If seasonal or weather changes occur, there may be considerable variation from the ideal conditions of water and air temperate. This can cause dolphins to migrate temporarily to different locations satisfying their environmental needs.

The food requirement of the dolphin is usually met by the variety in fishes, cephalopods and crustaceans. They hunt one type of species available in their inhabiting location. If this were to move out, the dolphins then turn to hunting other preys which may still be available. Rarely though, they pursue the preys before returning to their location or moving away to hunting other prey species.

The dolphins are the topmost in the food-chain as far as marine life forms are concerned. But they are preyed up on by the sharks and Killer Whales. In order to protect themselves and their calves, the dolphin pods do not inhabit close to the areas with concentrated shark population. For short time spans, dolphins move out of their locations in order to protect the young calves and lessen the chances of being hunted by sharks.

There are studies which propose that the dolphins migrate to particular areas in the oceans and seas for the purpose of mating. The requirement of favorable conditions during birthing seasons like temperate water and air temperatures, abundance of food, reduced risk from predators and better survival chances of calves seems to be probable reason for migration for mating as well as breeding. However, more proof is needed to prove this theory.

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