Bottlenose Dolphin

 Bottlenose dolphin range (in blue)   -  Size comparison against an average human.

Bottlenose dolphins, the genus Tursiops, are the most common and well-known members of the family Delphinidae, the family of oceanic dolphins. Recent molecular studies show the genus contains two species, the Common Bottlenose Dolphin (Tursiops truncatus) and the Indo-Pacific Bottlenose Dolphin (Tursiops aduncus), where previous thought was that this was one species. Bottlenose dolphins inhabit warm and temperate seas worldwide.

Bottlenose dolphins live in groups called pods that typically number about 15 dolphins, but group size varies from solitary bottlenose dolphins up to groups of over 100 or even occasionally over 1000 animals. Their diet consists mainly of forage fish. Dolphin groups often work as a team to harvest schools of fish, but they also hunt individually. Dolphins search for prey primarily using echolocation, which is similar to sonar. They emit clicking sounds and listen for the return echo to determine the location and shape of nearby items, including potential prey. Bottlenose dolphins also use sound for communication. Sounds used for communication include squeaks and whistles emitted from the blowhole and sounds emitted through body language, such as leaping from the water and slapping their tails on the water.

There have been numerous investigations of bottlenose dolphin intelligence. Such testing has included tests of mimicry, use of artificial language, object categorization and self-recognition. This intelligence has driven considerable interaction with humans. Bottlenose dolphins are popular from aquarium shows and television programs such as Flipper. They have also been trained by militaries for tasks such as locating sea mines or detecting and marking enemy divers. In some areas they cooperate with local fishermen by driving fish towards the fishermen and eating the fish that escape the fishermen's nets. Some encounters with humans are harmful to the dolphins: people hunt bottlenose dolphins for food, and dolphins are killed inadvertently as a bycatch of tuna fishing.

Heaviside Dolphin

Heaviside Dolphine range (in blue) - Size comparison against an average human. 

The Haviside's Dolphin (Cephalorhynchus heavisidii), or mistakenly the Heaviside's Dolphin, is a small dolphin that is found off the coast of Namibia and the west coast of South Africa. It is one of four dolphins in the Cephalorhychus genus - the others being the Chilean Dolphin, Hector's Dolphin and Commerson's Dolphin.

Although sightings of the species are not uncommon off the Skeleton Coast of Namibia, Haviside's Dolphins have not been systematically studied by scientists.
They have been recorded off the coast of northern Namibia at 17° S and as far south as the southern tip of South Africa. Sightings are often recorded from major population centres such as Cape Town and towns such as Walvis Bay. Sightings are likely from Lambert's Bay either from the shore or from boat trips run from the Harbour. No estimates of abundance exist.

Dusky Dolphin

Dusky Dolphine range (in blue)   -  Size comparison against an average human.

The Dusky Dolphin (Lagenorhynchus obscurus) is a highly gregarious and acrobatic dolphin found in coastal waters in the Southern Hemisphere. It was first identified by John Edward Gray in 1828. It is very closely genetically related to the Pacific White-sided Dolphin, but current scientific consensus is that they are distinct species.

The population of Dusky Dolphins is unknown, but authorities do not fear for the survival of the species at the moment. The Dusky Dolphin is distributed in coastal waters of Chile, Argentina and the Falkland Islands, Namibia and the west coast of South Africa and all around New Zealand. There may also be resident populations off Tasmania and New South Wales and several small islands in the South Atlantic and Indian Oceans. An aerial survey off Patagonia in the mid-1990s indicated that there was a local population in excess of 7,000 individuals. Duskies can move over great distances (one individual had a confirmed range of 780 nautical miles) (1,440 km). However it is not believed that they follow a migatory pattern.

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