[7] Numerous investigations of bottlenose dolphin intelligence have been conducted, examining mimicry, use of artificial language, object categorization, and self-recognition.

[10] Scientists have been long aware of the fact that the Tursiops dolphins might consist of more than one species, as there is extensive variation in color and morphology along its range.

[11] Since the late 1990s and early 2000s, most researchers acknowledged the existence of two species:[12] the common bottlenose dolphin (T. truncatus), found in coastal and oceanic habitats of most tropical to temperate oceans, and the Indo-Pacific bottlenose dolphin (T. aduncus), that lives in coastal waters around India, northern Australia, South China, the Red Sea, and the eastern coast of Africa.

[14] Also, evidence has been accumulating to validate the existence of a separate species, Lahille's bottlenose dolphin, T. gephyreus,[15][16][17][18] that occurs in coastal waters of Argentina, Uruguay and southern Brazil.

The Society for Marine Mammalogy's Committee on Taxonomy presently recognizes three species of bottlenose dolphin: T. truncatus, T. aduncus, and T. erebennus.

[25] However, more recent studies indicate that this is a consequence of reticulate evolution (such as past hybridization between Stenella and ancestral Tursiops) and incomplete lineage sorting, and thus support T. truncatus and T. aduncus belonging to the same genus.

A bottlenose dolphin discovered in Japan has two additional pectoral fins, or "hind legs", at the tail, about the size of a human's pair of hands.

The calves are born with two slender rows of whiskers along their snout, which fall off soon after birth, leaving behind a series of dimples known as vibrissal pits able to sense electric fields.

The eyes are located at the sides of the head and have a tapetum lucidum, or reflecting membrane, at the back of the retina, which aids vision in dim light.

[54] Bottlenose dolphins are able to detect salty, sweet, bitter (quinine sulphate), and sour (citric acid) tastes, but this has not been well-studied.

[54] In 2022, a study at the University of St Andrews in Scotland found that dolphins were able to identify their "friends" and family members by the taste of their urine in the water.

[57] Examples of body language include leaping out of the water, snapping jaws, slapping the tail on the surface and butting heads.

[61] The researchers stated that CDS benefits for humans are cueing the child to pay attention, long-term bonding, and promoting the development of lifelong vocal learning, with parallels in these bottlenose dolphins in an example of convergent evolution.

[64] The burst-pulsed sounds (which are more complex and varied than the whistles) are used "to avoid physical aggression in situations of high excitement", such as when they are competing for the same piece of food, for example.

In Shark Bay, off Western Australia, dolphins place a marine sponge on their rostrum, presumably to protect it when searching for food on the sandy sea bottom.

[82] Along the beaches and tidal marshes of South Carolina and Georgia in the United States, bottlenose dolphins cooperatively herd prey fish onto steep and sandy banks in a practice known as "strand feeding".

[83] While initially documented in South Carolina and Georgia, strand feeding has also been observed in Louisiana, Texas, Baja California, Ecuador, and Australia.

[87][88] Near Adelaide, in South Australia, several bottlenose dolphins "tail-walk", whereby they elevate the upper part of their bodies vertically out of the water, and propel themselves along the surface with powerful tail movements.

[93][90] The bottlenose dolphins of John's Pass in Boca Ciega Bay, St. Petersburg, Florida, exhibit a rare form of self-decoration and social object use called grass-wearing.

[109] In Shark Bay, male Indo-Pacific bottlenose dolphins have been observed working in pairs or larger groups to follow and/or restrict the movement of a female for weeks at a time, waiting for her to become sexually receptive.

[22] Georgetown University professor Janet Mann argues the strong personal behavior among male calves is about bond formation and benefits the species in an evolutionary context.

Shortly, a playful bottlenose dolphin known to local residents as Moko arrived and, after apparently vocalizing at the whales, led them 200 m (660 ft) along a sandbar to the open sea, saving them from imminent euthanasia.

[131] In 2019 a female was observed caring for a juvenile melon-headed whale, the first reported instance of a bottlenose dolphin adopting a non-conspecific infant.

[156] Tião was a well-known solitary male bottlenose dolphin that was first spotted in the town of São Sebastião in Brazil around 1994 and frequently allowed humans to interact with him.

[157] The popular television show Flipper, created by Ivan Tors, portrayed a bottlenose dolphin[158] in a friendly relationship with two boys, Sandy and Bud.

[160] Dolphin Tale, directed by Charles Martin Smith, starring Nathan Gamble, Ashley Judd, Harry Connick Jr., Morgan Freeman, Cozi Zuehlsdorff and Kris Kristofferson, is based on the real-life story of the dolphin Winter, who was rescued from a crab trap in December 2005 and lost her tail, but learned to swim with a prosthetic one.

[163] Factual descriptions of the dolphins date back into antiquity — the writings of Aristotle, Oppian and Pliny the Elder all mention the species.

The population in the Moray Firth in Scotland is estimated to consist of around 190 individuals, and are under threat from harassment, traumatic injury, water pollution and reduction in food availability.

[171] Likewise, an isolated population in Doubtful Sound, New Zealand, is in decline due to calf loss coincident to an increase in warm freshwater discharge into the fiord.

[173] One of the largest coastal populations of bottlenose dolphins in Shark Bay, Western Australia was forecast to be stable with little variation in mortality over time (Manlik et al.