Striped Dolphin

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.

## Description

Stenella coeruleoalba, otherwise known as striped dolphins, are a fascinating member of the family Delphinidae.  S. coeruleoalba ranges in body length from 220cm to 236cm. Like many other delphinids, striped dolphins have a fusiform body, tall dorsal fins, long, narrow flippers, and a prominent beak (Archer and Perrin, 1999).  S. coeruleoalba can be identified from other delphinids by their distinctive color and stripe patterns. Striped dolphins are typically bluish-gray in color with a dark dorsal cape and light (usually white) ventral coloration. They are called 'striped' dolphins because of the dark bluish-black stripe running across the entire length of the body, from the eye to the anus, and because they possess black flipper stripes

## Range and Habitat

Stenella coeruleoalba is found in warm-temperate and tropical seas throughout the world.  S. coeruleoalba has been observed in the Mediterranean Sea, eastern and western Pacific Ocean, Atlantic Ocean, Indian Ocean, Caribbean Sea, and in the northern Gulf of Mexico. Striped dolphins occupy both offshore and inshore warm-temperate and tropical waters.

## Behavior

Group size in S. coeruleoalba ranges from a few individuals to over one-thousand individuals, but most schools consist of 100-500 dolphins. Three different kinds of schools often occur: juvenile, breeding adults, and non-breeding adults. Calves do not usually join the juvenile school until one or two years after weaning. As females reach the transition stage between juvenile and adult, they usually join the non-breeding adults, only a small number go straight to the breeding school. However, as males join an adult group, equal numbers tend to join the breeding and non-breeding schools.

Striped dolphins are very active, performing aerial maneuvers such as breaching (jumping out of the water), chin slaps, bow-riding (swimming along the wave created by a boat or ship, while often twisting and jumping) and a unique behavior called "roto-tailing," in which "they make high arcing jumps while violently and rapidly performing several rotations with the tail before reentering the water". Like other delphinids, striped dolphins often vocalize with clicks and whistles, which presumably function in communication.

## Diet

The adult striped dolphin eats fish, squid, octopus, krill, and other crustaceans. Mediterranean striped dolphins seem to prey primarily on cephalopods (50-100% of stomach contents), while northeastern Atlantic striped dolphins most often prey on fish, frequently cod. They mainly feed on cephalopods, crustaceans, and bony fishes. They feed anywhere within the water column where prey is concentrated, and they can dive to depths of 700 m to hunt deeper-dwelling species.

## Reproduction

The age of sexual maturity is quite variable within sexes. Males reach sexual maturity between the ages of 7 and 15, and females become sexually mature between 5 and 13 years of age. The mating season of the striped dolphin is in the winter and early summer in the western north Pacific, while it occurs in the fall in the Mediterranean (Archer and Perrin, 1999). The gestation period of striped dolphins lasts 12-13 months. Females typically have a four year calving interval, having a resting period of approximately 2-6 months between lactation and the next mating. Fetuses grow at an approximate rate of 0.29cm/day. At birth, striped dolphins are 90-100cm long (differing slightly between ranges) and weigh approximately 11.3kg. Young calves then nurse for almost 16 months.