Rough-toothed Dolphin - Behaviour and Diet

Behaviour and Diet

Rough-toothed dolphins are typically social animals, although solitary individuals are also sighted. An average group has between ten and twenty members, but they can vary from as few as two to as many as ninety. Such groups are thought to be temporary assemblages, composed of smaller, more permanent groups of two to eight closely related individuals that occasionally join together with others. They have also been reported to school together with other species of dolphin, and with pilot whales, false killer whales, and humpback whales.

Rough-toothed dolphins have been reported to bow-ride on a number of occasions, although apparently they do not do so as frequently as many other dolphin species. They do, however, commonly "skim", by swimming with their heads and chin above the surface of the water. They are known to be able to dive to at least 50 metres (160 ft) and be able to stay underwater for at least fifteen minutes. Their echolocation clicks are unusually brief, lasting no more than 0.2 seconds, and have a relatively low frequency, ranging from 2.7 to 256 kHz, with a maximum peak frequency of 25 kHz. They also make longer whistles with a frequency between 3 and 12 kHz.

Although details of their diet are sketchy, the stomach contents of stranded dolphins have included such fish such as silversides, sauries, houndfish, smelts, cutlassfish, and various squid and octopuses. Predators on rough-toothed dolphins are thought to include killer whales and sharks.