The Atlantic Spotted Dolphin (Stenella frontalis) is a dolphin found in the Gulf Stream of the North Atlantic Ocean. Older members of the species have a very distinctive spotted colouration all over their body. The colouring of the Atlantic Spotted Dolphin varies enormously as they grow. Calves are a fairly uniform grey colour. When the calves are weaned, they then begin to get their spots. Juveniles have some dark spots on their belly, and white spots of their flanks.
Their back and dorsal fin are a darker grey than the rest of the body. As the animal matures the spots became denser and spread all over the body until at full physical maturation the body appears black with white spots. There are coastal and offshore groups and these can be quite different to each other. The offshore form tends to be smaller than the coastal and has fewer spots.
At full size Atlantic Spotted Dolphins are about 2.2 – 2.5 metres in length and weigh around 200 pounds. Atlantic Spotted Dolphins may easily be confused with the Common Bottlenose Dolphin and the Pantropical Spotted Dolphin when observed at sea.
In common with other species in its genus the Atlantic Spotted Dolphins is a gregarious creature. The Atlantic Spotted Dolphin is a fast swimmer, keen bow-rider and prone to acrobatic aerial displays.
Atlantic spotted dolphins have between 32 and 42 teeth in each row of the upper jaw and between 30 and 40 teeth in each row of the lower jaw.
Atlantic spotted dolphin Behaviour
The typical family group of the Atlantic spotted dolphin can consist of 50 individuals but is usually somewhere between 5 and 15. They are very vocal and active at the surface. Atlantic Spotted Dolphins will often group with other types of dolphins. It has also been observed that pods of Atlantic spotted dolphins can be formed along lines of gender, age and reproductive status.
On both coasts of northern Florida, moving groups may consist of up to 100 individuals and may attract other, smaller groups that join the large group briefly. Segregated schools of sub adults and adults without calves and of adults with calves have also been observed.
The Gulf of Mexico population (and possibly other populations as well) moves close to shore during summer. Usually, these dolphins are found over the offshore continental shelf.
Atlantic spotted dolphin Diet
Atlantic spotted dolphins tend to feed mainly on many varieties of fish and squid.
Atlantic spotted dolphin Communication
Like all dolphins, Atlantic Spotted Dolphins communicate by using ‘Sonar’ – a way of locating objects based on the reflection of sound waves rather than light.
Atlantic spotted dolphin Reproduction
Young Atlantic spotted dolphins are born after a gestation period of 11 or 12 months. They have no spots when they are born. They first start to develop spots about the time they are weaned. The Atlantic Spotted Dolphin has a life span of around 45 years.
Atlantic spotted dolphin Predators
Atlantic spotted dolphins are preyed upon by sharks.
Atlantic spotted dolphin Conservation
Atlantic Spotted Dolphins are an occasional target of harpoon fishermen and every year some creatures are trapped and killed in gill nets. However these activities are not currently believed to threatening the survival of the species.
Dolphins and Humans
Some Atlantic Spotted Dolphins, particularly some of those are around the Bahamas have become habituated to human contact. In these areas cruises to watch and even swim with the dolphins are common. Scientists have also taken advantage of the situation by attaching radio transmitters to the dorsal fins of some individuals and observing their movement patterns.