The history and behaviour of a solitary wild, but sociable, bottlenose dolphin (Tursiops truncatus) on the west coast of England and Wales

Summary

The description of the appearance, behaviour and movements of a wild bottlenose dolphin are given. The dolphin, which was a male, was measured as approximately 360 cm in length during May 1976. The dolphin was estimated to be a mature adult. Certain distinguishing permanent body scars on the head and dorsal fin areas, and a damaged tooth, were a convenient means of identification of the dolphin.

The movements of the dolphin were traced to April 1972. Between then and March 1975 it was resident in the coastal areas around the Isle of Man. Between April 1975 and January 1976 the dolphin had moved to and remained resident in the region around Milford Haven in Pembrokeshire. From January 1976 until December 1976, the dolphin moved south again, and patrolled an area stretching from St. Ives on the north coast of Cornwall to Falmouth on the south coast of Cornwall, although during most of this time favoured localities were St. Ives and Mousehole, where it remained for long periods. All areas which were ‘adopted’ for any length of time showed similarities, in that boating traffic, fishing activity, mooring buoys, and usually diving and swimming activities were present. The bays were usually about 10 m deep or less, often with rocky shore and sandy bottom.

Behaviour observed included playing with, chasing and manoeuvring boats, playing with divers, swimmers, and floating objects, interfering with boat propellors and outboard engines, indiscriminate sexual activity with boats, and a general sociable attitude to people. The dolphin was a solitary animal, and apart from one brief incident in the Isle of Man, was never seen with other dolphins.

The general history and behaviour of the dolphin in comparison with records of other similar incidences of sociable yet wild Cetacea, and also captive dolphins lead one to believe that this animal is quite healthy and normal, apart from the unusual aspect of his sociability with man.