Delphinus delphis, Linnaeus, 1758
Common dolphins are characterized by having a dark brownish-gray back, white belly and an hourglass-like pattern on the flanks, where the anterior color is yellow, and the posterior color is light gray. The color of the dorsal fin may be dark or beige. They have a dark line from the pectoral fin to the beak. They have a prominent dorsal fin and beak.
The gestation period is 10-11 months and they have a new calf every 1-3 years. Common dolphins are about 80-90 cm long at birth. Adults can reach 2.5m in length (they have an average of 2.2m). Females reach sexual maturity between 2 and 8 years, while males reach sexual maturity between 3 and 12 years.
The average weight is 150kg, but it can reach 200kg. They feed mainly on small fish and squid. The populations of this species are widely distributed in tropical and temperate waters, occurring mainly in areas of high productivity, in the Atlantic and Pacific oceans. In Portugal this species is widely distributed throughout the coast and also on oceanic waters. Dives have already been recorded at a depth of 200m. Average life expectancy is at least 25-30 years.
They are fast swimmers and acrobats. Spotted frequently in large, active groups. The size of the group varies seasonally depending on the time of day. Often, they surf on the waves of boats. However, when the group includes many calves, they avoid the boats and form a closer group when scared. The dives can last 8 minutes, but usually between 10 seconds and 2 minutes. They can associate with other animals in feeding areas.