Oceanic Dolphin - Characteristics

Characteristics

The Delphinidae are the most diverse of the cetacean families, with numerous variations between species. They range in size from 1.2 metres (3.9 ft) and 40 kilograms (88 lb) (Haviside's dolphin), up to 9 metres (30 ft) and 10 tonnes (the Orca). Most species weigh between approximately 50 and 200 kilograms (110 and 440 lb). They typically have a curved dorsal fin, a clear 'beak' at the front of the head, and a forehead melon, although there are exceptions to all of these rules. They have a wide range of colors and patterns.

Most delphinids primarily eat fish, along with a smaller number of squid and small crustaceans, but some species specialise in eating squid, or, in the case of the Orca, also eat marine mammals. All, however, are purely carnivorous. They typically have between 100 and 200 teeth, although a few species have considerably fewer.

Delphinids travel in large pods, which may number a thousand individuals in some species. Each pod forages over a range of a few dozen to a few hundred square miles. Some pods have a loose social structure, with individuals frequently joining or leaving, but others seem to be more permanent, perhaps dominated by a male and a 'harem' of females. Individuals communicate by sound, producing low frequency whistles, and also produce high frequency broadband clicks of 80-220 kHz, which are primarily used for echolocation. Gestation lasts from ten to twelve months, and results in the birth of a single calf.