Striped Dolphin

## Description

The striped dolphin (Stenella coeruleoalba ) is an extensively studied dolphin found in temperate and tropical waters of all the world's oceans. It is a member of the oceanic dolphin family, Delphinidae.

## Appearance

Striped dolphin has a typical shape for a dolphin, exhibiting a blue skin color with a white to light grey stripes, running along the spine: this unique coloration distinguishes the animal from other dolphin species. Meanwhile, the coloration of this animal may vary greatly depending on habitat and helping the dolphin easily merge with the environment. The belly of the animal is lighter than sides. As the dolphins age, the coloration and stripes on their body become more emphatic. In some parts of their range, the Striped dolphins are occasionally called 'streakers' due to their ability of moving very fast in order to avoid boats.

## Distribution

Striped dolphins inhabit both offshore and inshore areas, preferring warm-temperate and tropical waters. The area of their distribution covers a huge territory, including the Atlantic Ocean, Pacific Ocean, Indian Ocean, Mediterranean Sea, Black Sea and the northern Gulf of Mexico.

## Behavior

Striped dolphins are highly social animals, known to gather in large schools, consisting of more than 1000 individuals. However, they most commonly appear in smaller groups of 100 - 500 animals. Meanwhile, groups of this species differ in their type. Thus, there are groups of juvenile, breeding adults and non-breeding adults. Each dolphin moves around to corresponding groups throughout its life. These active and playful animals are known to perform a variety of aerial maneuvers. They can often be observed bow-riding: enthusiastically swimming along a vessel and accompanying the performance with twists and jumps. Striped dolphins are also known for "roto-tailing": this is when a dolphin jumps high, doing several quick and sharp rotations with its tail, and then dives back into the water. Other maneuvers they perform include chin slaps as well as breaching or jumping out of water.

## Diet

These dolphins are opportunistic feeders, though they are primarily piscivorous and molluscivorous. They generally prefer fish (especially lantern fish), cephalopods and crustaceans.

## Reproduction

Currently, very little is known about the mating system of striped dolphins, although the animals are believed to be polygynous. In the western north Pacific region of their range, these animals usually mate in winter and summer months. Meanwhile, those in the Mediterranean region tend to mate in the autumn. Females usually give birth every 4 years. Gestation period lasts for 12 - 13 months. Females and their young are known to form mothers-and-calf schools. Newborn calves live in these groups with their mothers for 16 months, after which they are weaned. According to scientific studies, sexual maturity of these dolphins depends more on their length than the age. Thus, the animals are ready to mate at a length of 7 feet (2 meters). When it comes the age, males of this species are usually able to mate within 7 - 15 years, whereas females are ready to mate at 5 - 13 years old.

## Population

### Population threats

The primary threats to this species population include commercial fisheries and hunting for meat. Currently, Striped dolphins also suffer from degradation of their natural habitat.

### Population number

According to the IUCN Red List, the worldwide population size of the Striped dolphin is over 2 million individuals, including estimated populations in following regions: the western North Pacific - 570,000 dolphins; the eastern tropical Pacific - 1,470,854 dolphins; the western Mediterranean excluding the Tyrrhenian Sea - 117,880 dolphins; the Bay of Biscay - 74,000 dolphins; the northern Gulf of Mexico - 3,325 dolphins; and the western North Atlantic off the US east coast - 94,462 dolphins. Currently, Striped dolphins are classified as least Concern (LC) on the IUCN Red List.

## Fun Facts for Kids

These dolphins are capable of diving as deep as 2,200 feet (670 meters) when foraging.

When resting, Striped dolphins never fall entirely asleep: they are always partially conscious in order to occasionally come up to the surface for air as well as defend themselves from possible threats.

Striped dolphins socialize mainly with conspecifics. They do not tend to associate with other animals including other dolphin species.

When swimming or performing aerial maneuvers, these animals are known to make high leaps of up to 20 feet above the surface.

The scientific name of the species is 'Stenella coeruleoalba', where 'coeruleoalba' is a combination of two Latin words: "caeruleus", meaning sky blue; and "albus", which means white. The animal is so called due to its unique dorsal coloration lateral portions of its body.

Striped dolphins appear to be even more playful and active than other dolphin species. These animals are known to perform a wide variety of tricks and communicate with conspecifics through a number of whistles and clicks.