The long-beaked common dolphin is a species of common dolphin. It has a more restricted range than the short-beaked common dolphin. It has a disjointed range in coastal areas in tropical and warmer temperate oceans. The range includes parts of western and southernAfrica, much of western South America, central California to central Mexico, coastal Peru, areas around Japan, Korea and Taiwan, and possibly near Oman. Vagrants have been recorded as far north as Vancouver Island. They live in shallow, warmer temperature waters near the coast. They also live in the tropical and subtropical regions.
The long-beaked common dolphin is medium-sized, but smaller than the more popular bottlenose dolphin. Adults range between, long, and can weigh between, although a range between is more common. Males are generally longer and heavier. The color pattern on the body is unusual. The back is dark and the belly is white, while on each side is an hourglass pattern colored light grey, yellow or gold in front and dirty grey in back. This species also has a rounded melon on tops of their heads used for echolocation. It has a long, thin rostrum with up to 60 small, sharp, interlocking teeth on each side of each jaw. They have more teeth than any other delphinids.
Taxonomy
The long-beaked common dolphin is a member of the common dolphin genus, Delphinus within the dolphin family, Delphinidae in the cetaceans order. Until the mid-1990s, the different forms within Delphinus were not recognized as separate species, but were all considered members of the species D. delphis. In 1994, Heyning and Perrin did research on these species and then Kingston and Rosel confirmed there were two separate species. Currently, the two recognized species of Delphinus are the short-beaked common dolphin and the long-beaked common dolphin. The long-beaked common dolphin is generally larger with a longer beak than the short-beaked common dolphin and has a longer rostrum. The Indo-Pacific common dolphin is sometimes considered a separate species, but is more often considered a form of the long-beaked common dolphin.
Behavior
Long-beaked common dolphins can live in aggregations of hundreds or even thousands. Within these large groups, smaller subgroups of 10 to 30, related in either sex or age, typically are found. They sometimes associate with other dolphin species, such as pilot whales. They have also been observed bow riding on baleen whales, and they also bow ride on boats. Breaching behavior and aerial acrobatics are common with this species.
Diet
The long-beaked common dolphin has a varied diet consisting of small schooling fish, such as sardines, anchovies, mackerels, pilchards, mullet, drum or croaker. These dolphins may occasionally eat small cephalopods such as octopuses and squid, and more rarely eat small crustaceans like large shrimp or small crab. Since they gather in huge superpods and there is seldom enough food in one place to support all of them, smaller groups leave the main pod for a few hours to feed. They are able to dive in the water to about and hold their breath for up to 8 minutes to catch prey.
Reproduction
The long-beaked common dolphin has a gestation period of 10 to 11 months typically during spring or autumn. The newborn calf has a length of between and a weight of about. The young and juvenile dolphins coloration and patterns are darker than the adults. Typical interbirth interval ranges from one to three years. In captivity, this dolphin has hybridized with the common bottlenose dolphin. One of the hybrids has been bred back to a bottlenose dolphin, demonstrating such hybrids are fertile. The long-beaked common dolphin can live up to 40 years.
Relationship to humans and other species
Long-beaked common dolphins are not common in human care as they are extremely difficult to keep in captivity. In the wild, however, they have been seen travelling with bottle-nosed dolphins, pilot whales, and yellowfin tuna.
