Tursiops truncatus

Names

Azores : Toninha brava - POR : Roaz - ITA : Tursiope - SPAIN : Nariz de bottela - GB : Bottlenose dolphin - GER : Groertümmler - NEDER : Tuimelaar - SWEEDS : Ôresvin - NOORS : tumler - DEENS : Øresvin - JAP : Bando iruka

Biology

The average adult size is slightly under 3 m long and males are larger than females. The latter have a maximum length of 3.7 m, while the males can reach 4 m long. Their weight varies between 150 and 350 kg, but exceptionally they can reach 650 kg. They have 18 to 26 pairs of robust teeth in each jaw. The body is slender and their general coloration is dark gray with a tendency to get lighter with increasing age. The melon is convex, the beak is distinct, and the gums are visible against the upper jaw. Gestation lasts for 12 months, and calves are often nursed for 12 to 18 months. Newborns measure between 0.9 to 1.3 m and weigh about 30 kg. Females bear a single calf every second or third year. Bottlenose dolphins are very social and they seem to help each other a great deal throughout life. For instance the way in which they help a female with a newborn at the time of birth, in hunting, or by fighting an outside aggressor. They feed on pelagic fish, mullets, eels, rays, squids, cuttlefish, and sometimes shrimp.. They can live 25 to 40 years. This species emits different echolocation sounds: clicks with frequencies ranging from 0.1 to 300 kHz, whistles and barks with a frequency of 0.2 to 20 kHz.

Observation

The bottlenose dolphin, better known as "Flipper" in the famous American TV series, or the involuntary star and victim of delphinariums, is frequently observed in the Azores in the company of pilot whales. A large group of 50 to 80 individuals - no doubt, year round residents on the south side of Pico - can be seen very close to the coast in about 1/3 of our ocean trips. They can be confused with other species such as juvenile spotted dolphins that live in the same area and the rough-toothed dolphins. However, the bottlenose are larger than the rough-toothed dolphins, which have a very distinct head and also are not common in the Azores. Despite living in the same regions as the pilot whales and the Risso«s dolphins, the bottlenose dolphins are not easily confused with them since the latter do not have a beak. Exceptional cases of hybridisation between this species and the other 4 species have been reported. The bottlenose dolphin emerges every 2 to 3 minutes while travelling and it can submerge for as long as 10 minutes. Their cruise speed is about 5 knots and they can swim to a maximum speed of 25 knots for short periods of time.