Common Bottlenose Dolphin – Tursiops truncatus


The Common Bottlenose Dolphin belongs to the family of the dolphins (Delphinidae) and is thus part of the order of the Whales (Cetacea). Tursiops truncatus was first described in 1821 by Montagu.

Due the series Flipper it is probably the most famous type of dolphin and is presented in many shows. However, the Short-Beaked Common Dolphin is more widespread in European waters.

Whether the Common Bottlenose Dolphin is one or more species is controversial. Some zoologists name up to 3 species:

  • Common Bottlenose Dolphin (Tursiops truncatus)
  • Indo-Pacific Bottlenose Dolphin (Tursiops aduncus)

  • Pacific Bottlenose Dolphin (Tursiops gillii)

There is also a subspecies that lives in the Black Sea which is called Tursiops truncatus ponticus.

Description

The Common Bottlenose Dolphin are grey in colour, with the abdomen being slightly brighter.

It reaches up to 4m length and a maximum weight of 650kg, although it is usually between 150 and 300kg.

The short muzzle is conspicuous, which is why it is called Bottlenose Dolphin. In addition, the snout has up to 80 teeth.

The sickle-shaped dorsal fin is also striking.

Habitat & Distribution

Common Bottlenose Dolphin Tursiops truncatus canary islands canaries atlantic ocean delphinidae cetacea cetaceans range map
CC BY-SA 3.0, Link

Tursiops truncatus is native to all three oceans and prefers the tropical and subtropical areas. It is also found in the Mediterranean Sea and more and more frequently in the North Sea.

Preferably, the animals stay close to the coast, although there are also schools in the open water.

When diving in the Canaries, it is very unlikely to encounter Tursiops truncatus, since the targeted approach is prohibited. However, you can often see it on Whale Watching trips.

Biology & Social Behaviour

The Common Bottlenose Dolphins has a predatory way of life. They prefer small fish, but cephalopods and crustaceans are also on its menu. It can find its prey through high-frequency clicks. This works like echolocation. Tursiops truncatus has ears, but most of the sound is passed threw the mouth into the inner ear. It also has good eyes.

It swims 60 to 100km a day and does dives to a depth of 500m. Usually the Common Bottlenose Dolphin comes to the surface every one to two minutes to get air. Nevertheless they can dive up to 4.5 minutes.

A school normally comprises two to fifteen animals and is led by an old male. In the Atlantic, a school has, for example, in average 5 animals. It also happens that hundreds of animals swim together. Young males form their own schools, so-called bachelor’s associations. It is also reported that grandparents supervise, protect and nurture their grandchildren!

Scientists have observed something very special in Shark Bay, West Australia. There, bottlenose dolphins use sponges as tools. They loosen them from the ground, push them over the muzzle, and thus have protection when looking for food in the seabed. Thereby, only 30 of 3000 existing individuals show this behaviour. The so-called Spongers (for sponge) had a significant genetic relationship. It is assumed that the behaviour is transmitted from mother to daughter.

Reproduction & Developement

Juveniles are born after about one year of gestation, measuring between 84 and 120cm and weighing 14 to 20kg. A birth can take up to two hours. In order not to drown, they are born with the tail fin first. Then the mother pushes the young animal to the surface so that it can breathe. Other members of the group protect the mother from possible attacks by any predators. There are occasional twin births. However, the young animals usually do not live long because there is not enough milk to feed both of them.

After birth, neither mother nor calf will sleep for about two weeks. The young animal stays with his mother for about 3 years, being nursed for about a year.

The Common Bottlenose Dolphins reaches an age of up to 25 years, while animals captivity are aged up to 50 years.

Communication

Tursiops truncatus communicates with specimens through whistling sounds. Each animal has a characteristic recognition tone.

Some scientists think that one can communicate with the animals by deciphering their language. The prevailing opinion, however, assumes that Common Bottlenose Dolphins have only a limited selection of signals. This allows them to identify theirselves and express their condition.

Sources

https://de.wikipedia.org/

http://www.marinespecies.org/

http://animaldiversity.org/accounts/Tursiops_truncatus/