Bottlenose dolphins (genus Tursiops) are most common and well-known members of the family of oceanic dolphin.
There are three species of bottlenose dolphins:
• the common bottlenose dolphin (Tursiops truncatus), found in the temperate, subtropical and tropical oceans worldwide.
• the Indo-Pacific bottlenose dolphin (Tursiops aduncus) found in the waters around India, northern Australia, South China, the Red Sea, and the eastern coast of Africa.
• the Burrunan dolphin (Tursiops australis) found only in waters off Australia’s southern and
Bottlenose dolphins have a lifespan of about 40 to 50 years. Females typically live 5-10 years longer
than males, with some females exceeding 60 years.
Bottlenose dolphins range in lengths from 2 to 4 meters (6.6 to 13.1 ft) and weight from 150 to 650 kilograms (330 to 1,430 lb).
Males are, on average, slightly longer and considerably heavier than females.
Differences in size also may be related to coastal and offshore ecotype variances, and geographical locations. Offshore ecotypes, adapted for cooler waters, tend to be larger than inshore ecotypes.
Bottlenose dolphins have a sleek, streamlined, fusiform body.
Their elongated upper and lower jaws form what is called a rostrum, or snout, which gives the animal
its common name. The real, functional nose is the blowhole on top of its head.
Eyes are on the sides of the head, near the corners of the mouth; eyes may move independently of each
Bottlenose dolphins seem to be always smiling because of the slight upturn to the corner of their mouths.
They have 80-100 cone-shaped teeth. Teeth are designed for grasping (not chewing) food.
Bottlenose dolphins are grey, varying from dark grey at the top near the dorsal fin to very light grey
and almost white at the underside. This countershading makes them hard to see; When viewed from above, a dolphin’s dark back surface blends with the murky depths. When seen from below, a dolphin’s lighter belly blends with the bright sea surface.
Their skin is smooth and feels rubbery. The outer skin layer (epidermis) is about 10 to 20 times thicker than the epidermis of terrestrial mammals.
Their forelimbs are pectoral flippers. Pectoral flippers have the major skeletal elements of land mammal forelimbs, but they are foreshortened and modified. The skeletal elements are rigidly supported by connective tissue.
Bottlenose dolphins are super swimmers, gliding through the water using their curved dorsal fin on
their back, a powerful tail and pointed flippers.
They typically swim at 5 to 11 km/h (3 to 7 mph), but are capable of bursts of up to 35 km/h (22 mph).
The bottlenose dolphin typically rises to the surface to breathe through its blowhole two to three times per minute, although it can remain submerged for up to 20 minutes.
The deepest dive ever recorded for a bottlenose dolphin was 300 meters (990 feet) by Tuffy, a bottlenose dolphin trained by the US Navy.
Bottlenose dolphins hear tones with a frequency up to 160 kHz with the greatest sensitivity ranging from 40 to 100 kHz. The average hearing range for humans is about 0.02 to 20 kHz.
Bottlenose dolphins have acute vision both in and out of the water. A dolphin’s eye is particularly adapted for seeing under water.
Dolphins have developed the ability to use echolocation, often known as sonar, to help them see better underwater. Scientists believe this ability probably evolved slowly over time. Echolocation allows
dolphins to “see” by interpreting the echoes of sound waves that bounce off of objects near them in
the water. Echolocation tells the dolphins the shape, size, speed, distance, and location of the
Dolphins have to be conscious to breath. This means that they cannot go into a full deep sleep, because then they would suffocate. Dolphins have “solved” that by letting one half of their brain
sleep at a time. This has been determined by doing EEG studies on dolphins.
Bottlenose dolphins live in groups typically of 10–30 members, called pods, but group size varies from single individuals up to more than 1,000.
Bottlenose dolphins communicate with each other in different ways. They squeak and whistle and use body language—leaping as high as 6 meters (20 feet) in the air, snapping their jaws, slapping their tails on the surface of the water, and even butting heads.
Each dolphin has a unique whistle that functions like a name, allowing the marine mammals to keep
close social bonds.
A bottlenose dolphin’s diet consists mainly of fish, squid and crustaceans. An adult dolphin may eat 7 – 13.5 kilograms (15 – 30 pounds) of food each day.
Bottlenose Dolphins often work as a team to harvest fish schools, but they also hunt individually. They search for prey primarily using echolocation.
Bottlenose dolphins may breed throughout the year. Male and female bottlenose dolphins have multiple mates in a given reproductive season.
The gestation period is about 12 months. The young are born in shallow water, sometimes assisted by a (possibly male) “midwife”, and usually only a single calf is born (twins are rare). The calf suckles for 18 months to up to 8 years, and continues to closely associate with its mother for several years after weaning.
Some large shark species, such as the tiger shark, the dusky shark, the great white shark and the bull shark, prey on the bottlenose dolphin, especially calves.
The bottlenose dolphin is capable of defending itself by charging the predator; dolphin ‘mobbing’
behavior of sharks can occasionally prove fatal for the shark.
While bottlenose dolphins are not categorized as endangered by the IUCN Red List of Threatened Species, they are undoubtedly at risk from the commercial fishing industry and habitat destruction.
Bottlenose dolphins have the second largest encephalization levels (the amount of brain mass related to an animal’s total body mass) of any mammal on Earth (humans have the largest), which more than likely contributes to their incredibly high intelligence and emotional intelligence.
Research suggests that bottlenose dolphins are self-aware, a trait which is considered to be a sign of
highly-developed, abstract thinking. One such indicator is that they have been shown to be able to
recognise themselves in a mirror.
They can use tools and transmit cultural knowledge across generations, and their considerable
intelligence has driven interaction with humans.
Occasionally, they rescue injured divers by raising them to the surface. They also do this to help
injured members of their own species.
Bottlenose dolphins have the longest social memories of any nonhuman species. They have been shown to recognize the unique whistles of individual dolphins they once associated with some 20 years after becoming separated from them.
Bottlenose dolphins gained popularity from aquarium shows and television programs such as Flipper.