Common dolphins are frequently seen on our Great White Shark trips and are widely distributed in the offshore waters along the entire coast of South Africa. There are two species of common dolphin, the long-beaked and short-beaked common dolphin. The main species that we see on our trips is the long-beaked common dolphin.
Physical Description & Colour
Common dolphins can easily be identified by their bright, colour-contrasting patters. The sides are light grey in colour behind the dorsal fin, and a yellowish-tan colour in front of the dorsal fin, which creates their distinct hourglass pattern. The back is dark grey-to-black in colour, stretching from the top of the head to the tail, and dipping to a V on the sides below the dorsal fin. The belly is white in colour. Common Dolphins have slender but solid bodies, with a long beak and a pointed triangular-shaped dorsal fin located in the middle of the back.
Length & Weight
Common dolphins are relatively small dolphins that can reach lengths of 1.9 and 2.6 metres, and weigh between 80 kg and 235 kg. At similar ages, the males are slightly larger than the females.
Common dolphins are found in all tropical and warm-temperate waters. The long-beaked common dolphin, which is the species that we often see, is found in more coastal waters; and the short-beaked common dolphin is mainly found in offshore waters.
Mating & Breeding
Common dolphins normally reach sexual maturity between 3 to 4 years of age, or when they reach 1.8 to 2.1 metres in length. Females normally give birth to a single calf after a 10 to 11 month gestation period. The calves are normally around 76 to 86 cm in length at birth, and weigh around 10 kg.
Common dolphins are active predators and their diet mainly consists of squid and small schooling fish, such as anchovies, sardines and pilchards. Small groups of common dolphins may work together to heard schools of prey, and they are often associated with diving birds and feeding whales.
Common dolphins are usually found in large social groups of between 100 and 500 animals, but have occasionally been seen in larger groups of thousands of individuals. They are fast swimmers and are often seen breaching and porpoising out of the water. They will also often approach ships to “bow-ride” for long periods of time.
This pic was taken by David Jenkins. Many thanks to him.