Bottlenose dolphin
Bottlenose dolphins are toothed whales in the genus Tursiops. They are common, cosmopolitan members of the family Delphinidae, the family of oceanic dolphins.[3] Molecular studies show the genus contains three species: the common bottlenose dolphin (Tursiops truncatus), the Indo-Pacific bottlenose dolphin (Tursiops aduncus), and Tamanend's bottlenose dolphin (Tursiops erebennus).[4][5] Others, like the Burrunan dolphin (Tursiops (aduncus) australis), may be alternately considered their own species or be subspecies of T. aduncus.[6] Bottlenose dolphins inhabit warm and temperate seas worldwide, being found everywhere except for the Arctic and Antarctic Circle regions. Their name derives from the Latin tursio (dolphin) and truncatus for the truncated teeth (the type specimen was old and had worn down teeth; this is not a typical characteristic of most members of the species).[7]
This article is about the genus of bottlenose dolphins. For the common species, see Common bottlenose dolphin.
Numerous investigations of bottlenose dolphin intelligence have been conducted, examining mimicry, use of artificial language, object categorization, and self-recognition. They can use tools (sponging; using marine sponges to forage for food sources they normally could not access)[8] and transmit cultural knowledge from generation to generation, and their considerable intelligence has driven interaction with humans. Bottlenose dolphins gained popularity from aquarium shows and television programs such as Flipper. They have also been trained by militaries to locate sea mines or detect and mark enemy divers. In some areas, they cooperate with local fishermen by driving fish into their nets and eating the fish that escape. Some encounters with humans are harmful to the dolphins: people hunt them for food, and dolphins are killed inadvertently as a bycatch of tuna fishing and by getting caught in crab traps.
Bottlenose dolphins have the third largest encephalization levels of any mammal on Earth (humans have the largest, followed by Northern Right whale dolphins), sharing close ratios with those of humans and other cetaceans, while being twice as high of other great apes.[9] This more than likely contributes to their high intelligence.[10]
Description[edit]
The bottlenose dolphin weighs an average of 300 kg (660 pounds), but can range from 150 and 650 kg (330 and 1,430 lb).[37] It can reach a length of just over 4 meters (13 feet). Its color varies considerably, is usually dark gray on the back and lighter gray on the flanks, but it can be bluish-grey, brownish-grey, or even nearly black, and is often darker on the back from the rostrum to behind the dorsal fin. This is called countershading and is a form of camouflage. Older dolphins sometimes have a few spots.
Bottlenose dolphins can live for more than 40 years. Females typically live 5–10 years longer than males, with some females exceeding 60 years.[38][39][40] This extreme age is rare and less than 2% of all Bottlenose dolphins will live longer than 60 years.[41] Bottlenose dolphins can jump to a height of 6 metres (20 feet) in the air.[42]
Ecology[edit]
Feeding[edit]
Fish is one of the main items in the dolphin diet. They also eat shrimps, squid, mollusks, and cuttlefish, and only swallow the soft parts. They eat 22 pounds of fish a day. When they encounter a shoal of fish, they work as a team to herd them towards the shore to maximize the harvest.[22] They also hunt alone, often targeting bottom-dwelling species. The bottlenose dolphin sometimes hits a fish with its fluke, sometimes knocking it out of the water, using a strategy called "fish whacking".[39][126] "Strand feeding" is an inherited feeding technique used by bottlenose dolphins near and around coastal regions of Georgia and South Carolina. When a pod finds a school of fish, they will circle the school and trap the fish in a mini whirlpool. Then, the dolphins will charge at the school and push their bodies up onto a mud-flat, forcing the fish on the mud-flat, as well. The dolphins then crawl around on their sides, consuming the fish they washed up on shore. This happens only during low tides.[127]
One type of feeding behavior seen in bottlenose dolphins is mud ring feeding.[128]
Bottlenose dolphins conflict with small-scale coastal commercial fisheries in some Mediterranean areas. Common bottlenose dolphins are probably attracted to fishing nets because they offer a concentrated food source.[129]