Measuring at 6 ft. long or less, Heaviside’s dolphin is a fairly small species of dolphin that can be found living off the southwest coast of Africa. Sometimes mistaken for one of the porpoise species (due to their small body, beak-less face, and stocky shape), these dolphins are known for their ability to leap vertically out of the water and dive back into the ocean with minimal sound or disturbance to the water.
Although Heaviside’s dolphins can appear to be shy at times, these dolphins have also been observed approaching boats, bow riding, and following ships as they pass by. The outgoing/shy nature of these marine mammals can vary from one dolphin or pod to the next, so observers can never be sure whether these dolphins are likely to approach them or keep their distance.
Physical Characteristics and Appearance
Heaviside’s dolphin is a small dolphin that reaches an average length of around 5 1/2 – 6 ft. and weighs around 160 lbs. when fully matured. These dolphins have a dark gray head, a large triangular dorsal fin, short paddle-shaped flippers, and hydrodynamic flukes. The majority of Heaviside’s dolphin is colored gray.
The underbody is white with white flanks that travel from the belly to the dolphin’s sides behind its flippers. The mid to lower back is covered in a dark gray skin tone, while the front half is a lighter shade of gray. This dolphin’s stocky body and blunted head often cause observers to confuse these dolphins for porpoises.
Diet and Hunting Methods
These dolphins consume a wide variety of different fish, squid, and octopus as the main source of their diet. As with other dolphin species, Heaviside’s dolphin likely uses echolocation to navigate the ocean and locate potential food.
Echolocation is vital when traveling in areas with little or no light. It allows dolphins to observe their surroundings using sound and provides them with the ability to detect prey, predators, and inanimate objects in complete darkness.
Habitat and Migration
Heaviside’s dolphin can be found swimming on the southwest coast of Africa from northern Namibia to the southern edge of South Africa. These dolphins primarily inhabit coastal waters and rarely risk swimming further out to sea.
Social Structure and Communication
These dolphins are most commonly seen traveling in groups of 5 – 10; however, they may temporarily aggregate into larger pods at certain times. Heaviside’s dolphin is a fairly social species of dolphin that enjoys spending time and playing with other dolphins among its pod.
Social activities for these dolphins include jumping and leaping out of the water vertically, then diving back into the ocean with a tiny splash or disturbance to the water. They are also known to bow ride and sometimes approach or follow boats and ships but can sometimes be shy when interacting with unfamiliar individuals.
Breeding and Reproduction
The average gestation period for Heaviside’s dolphins is around 10 – 11 months. Baby dolphins are nursed until they can fend and survive on their own. Both male and female dolphins reach sexual maturity between the ages of 8 – 10 and may begin mating and bearing their own offspring. While little is known about the lifespan of these dolphins, it is assumed that the average lifespan is around 20 years.
Threats and Predators
Heaviside’s dolphin is known to face several humans threats, including accidental bycatch, deliberate hunting, and habitat degradation.
- Bycatch
- Direct catch
- Habitat degradation
Bycatch – Heaviside’s dolphins are known to become caught in nets intended to capture fish. This can occur when a dolphin mistakes the captured fish for easy prey or when they do not notice the net drawn in front of them. Once a dolphin ends up caught in the net, it cannot resurface and ends up drowning as a result.
Direct catch/Hunting – These marine mammals are known to be hunted by poachers that may be interested in selling the meat for human consumption or want to use their meat as bait for other forms of prey.
Habitat degradation – In areas that have become commercialized or agriculturally developed, the risk of exposure to pollution, toxic chemicals collisions with boats, and other aquatic vehicles/machinery increases, making it more difficult for these marine mammals to thrive in their natural habitat. As far as natural predators are concerned, information regarding potential predators of this species is data deficient.