- A-Z Animals
Common dolphin is the term used for two dolphin species, from the genus Delphinus. According to some sources, there might as well be another third species by the name of Arabian common dolphin, which is debatable. These are medium sized playful dolphins, living in tropical and warm temperate waters.
Common Dolphin is the name of 2 species of dolphins that are scientifically known by the Latin names given below:
Some studies suggest the existence of a third species known as Delphinus tropicalis but recent studies consider it as a regional variety.
There are stark similarities in the appearance of the 2 species of common dolphins except a few dissimilarities. Take a look at their physical characteristics:
Size : The 2 species of Common Dolphins have a medium size, growing as big as 8.2 ft, with an average of 6 ft approximately. Naturally the only point of differentiation is the size of the beak which is longer in the long-beaked common dolphins.
Weight : Their weight varies between 80 and 150 kg, but it might as well be as heavy as 235 kg. Males are heavier compared to the females. To be precise, Short-beaked ones may weigh around 440 pounds and the long-beaked ones between 170 and 500 pounds approximately.
Color : It is primarily dark on its back and the abdomen is white. On the sides of these common dolphins, there is a pattern in the shape of hourglass composed of yellow and grey at the front and dark grey at the rear.
Rostrums : Their rostrums are thin and elongated with interlocking sharp teeth on every side.
In east Atlantic waters, they inhabit from West Africa to Norway’s southern parts and in West Atlantic, from Florida till Newfoundland. In Pacific, it stretches from Japan till Australia. They are commonly spotted in Australian waters (Tasman Sea and south-east Indian Ocean) barring North Australian regions. They are also seen in Galapagos waters.
Long-beaked ones prefer living in shallow habitats but the short-beaked ones can be found at a depth of around 590 feet as well. Level of shallow water isn’t lesser than 180 m. They can live in cool temperate or tropical offshore waters. They live in open oceans and coastal regions in the Mediterranean. Basically, areas where they can forage on epipelagic fishes are their territories.
Some of their behavioral characteristics are:
Common dolphins exchange a range of sounds. They whistle and whine during social interactions which can be specific to a certain pod.
They have a varied diet which chiefly constitutes squids and schools of fishes. Apart from that, they hunt small fishes from the mid water and surface of the ocean. Food behavior is influenced by different locations and seasons. They have been reported to be subsisting on anchovies in the Mediterranean Sea.
They may move around to hunt for food but they are not typically migratory. Beyond Southern California and eastern Pacific, there have been movements based on seasons. Dolphins from north are south bound in Pacific Ocean, as studies have revealed. They have been noted traveling to warmer waters with the change of season. In the months starting from May till October, they have been found visiting oceanic waters off Scotland.
Sharks are the worst enemies of the babies while even as adults they face threats from whales and humans. Their life is at risk from parasites and diseases as well.
These are some of their adaptive features:
Season for mating may vary, but usually it happens during spring and fall.
The common dolphins mature at different intervals at different locations. In the Pacific region, the females mature by the age of 7 and males mature between the age of 7 and 12. Mating takes place when become almost 6 ft long. The mother gives birth to her offspring after a gestation period of 11 months. The ones inhabiting the Pacific, takes an interval of 3 years between another birth and those from the Black Sea takes just a year. Both the species have no such marked difference in reproduction pattern.
The calf measures around 3 ft after birth with a weight of 10 kg approximately. Weaning period of the babies also varies largely according to location, from 6 months to 19 months.
It generally lives for 20 years, which may even exceed to 35 years in the oceans.
No sub-species of these dolphins have been reported yet.
They are rarely held in captivity but they are often nursed in zoos only to be later released. Nevertheless, they were exhibited at SeaWorld in San Diego along with Bottlenose dolphins, performing shows like their counterparts.
They have been marked as Least Concern species by IUCN, hence they are not endangered.
Some fun facts for kids are:
Take a look at these playful dolphins in these pictures.