Dolphins are one of the most familiar and unique marine mammals known to people and occupy all the major oceans and seas of the world. Some species are even known to live in larger river systems. Dolphins belong in the kingdom anamalia; phylum, corata; class mammalia; order, cetacean; sub-order, odonteceti; family, delphinidae; genus, delphinus; and species, delphis. Dolphins are believed to have a long evolutionary past dating back several, tens of millions of years
Dolphins are very social creatures and use this group interaction for hunting, defense, and reproduction. Normally dolphins are found in groups or families of 2-40 members called pods. Larger groups in the hundreds have been reported and are referred to as herds.
Dolphins are carnivorous, predatory mammals and feed on fish, squid, octopus, cuttlefish, crabs, shrimps, and lobsters. They are regularly hunted by sharks, killer whales and in some places, Humans. Humans are the most dangerous predator of the dolphin and have decimated their existence. Humans have been known to kill dolphins for their meat, their fat, even for being pests to fishermen. Additionally, scientists are currently evaluating the effect of water and air pollution on dolphins.
Dolphins bear live young and usually give birth to one calf at a time, although they rarely give birth to twins. The mothers generally nurse and care for the calf for one to three years after the calf is born. Following the nursing stage, mothers usually stay with their young for up to eight years.
Dolphins usually have lifespans of about 30 years. Dolphins’ lifespans and some physical characteristics vary depending on their particular location and its ecosystem. For example, in the Gulf of Alaska there are few dolphin species, one of which is the pacific white-sided dolphin. This dolphin has a short, rounded beak with about 30 curved teeth in each side of the jaw, most likely specialized for eating clams and