Latin name

Tursiops aduncus

Other names

Tursiops aduncus

Identification

Common bottlenose dolphins have a fairly stocky body, a medium-length beak, and high, curved dorsal fins, while Indo-Pacific bottlenose dolphins are more slender and their beaks are longer and more graceful. The teeth can range from 23 to 29 on each upper and lower jaw and are more slender. The species is characterized by a complex vocal apparatus, which they control perfectly. With a gentle flick of their tail, dolphins periodically push themselves out of the water and perform the act of breathing. While one hemisphere is asleep, the other is awake. The maximum swimming speed is 40 km/h.

Features of fish fins

Dorsal fin high, on a broad base, semilunarly notched posteriorly. The pectoral fins are broad at the base, pointed toward the end, convex along the anterior edge, and concave along the thin posterior edge. Through the fins (pectoral, dorsal, and caudal), dolphins exchange heat with the water. Therefore, fish thrown ashore often die from overheating. Without water, the fins can permanently stop functioning, so dolphins are specially wetted and cooled during transport.

Fish colouring

This population has a slightly lighter blue coloration and a more pronounced cape, with a light stripe on the back below the dorsal fin, compared to the common dolphin-aphaline. However, these features are not always present; the most obvious difference may be the presence of black spots or blotches on the abdomen of adults.

Distribution

They inhabit the waters around India, northern Australia, southern China, the Red Sea and the east coast of Africa.

Habitat

They usually stay close to the shore as they have a benthic feeding pattern and are active during the day. 

Size

Size may vary depending on geographic location. Their average length is 2.6 m (8.5 ft) and weight is up to 230 kg (510 lb). Length at birth ranges from 0.84 to 1.5 m (2.8 to 4.9 ft).

Behavior

They live in groups that can number in the hundreds, but groups of five to 15 dolphins are most common. 

Interestingly, these dolphins pluck sponges from the bottom and carry them on their rostrum, apparently to explore the substrate in search of fish, perhaps as a tool.

Food and feeding habits

They feed on a wide variety of fish and cephalopods (especially squid).

Reproduction

Mating and births peak in the spring and summer, although in some regions mating and births occur throughout the year. The gestation period is approximately 12 months. Cubs reach a length of 0.84 to 1.5 m (2.8 to 4.9 ft) and weigh 9 to 21 kg (20 to 46 lb). They are weaned between 1.5 and 2.0 years of age, but may remain with their mothers for up to 5 years. The interval between births for females is usually 4.5 to 6 years. Life expectancy for this species is over 40 years.

Fishing

Fishing for these dolphins is a method of hunting them by driving them into a bay or onto a beach. Their escape is prevented by blocking their path to the open sea with boats and nets. In large numbers, dolphins are hunted primarily for their meat; some are captured for dolphinariums.

Relationship with a person

The most common cetacean in captivity worldwide.

They are not aggressive, usually do not attack humans, but show interest and may even rescue drowning humans.