Mesoplodon mirus

True, 1913 - True's beaked whale

Distinctive Characteristics

True's beaked whales are not known to differ substantially from other species of Mesoplodon, although they have a slightly bulging forehead and prominent beak.

These beaked whales are characterized by the position of the mandibular teeth at the very tip of the lower jaw. The teeth are oval in cross-section, lean forward, and are visible outside the closed mouth of adult males.

Can be confused with

At sea, True's beaked whales are difficult to distinguish from other species of Mesoplodon. The only other species in which males have oval teeth at the tip of the lower jaw is Longman's beaked whale; whose appearance is not known.


Both sexes are known to reach lengths of slightly over 5 m. Weights of up to 1400 kg have been recorded. Newborns are probably between 2 and 2.5 m.

Geographical Distribution

True's beaked whales are known only from strandings in Great Britain, from Florida to Nova Scotia in the North Atlantic, and from southeast Africa and southern Australia in the Indo-Pacific Ocean.

Biology and Behaviour

There is almost no information available on the natural history of this species of beaked whale. Stranded animals have had squid in their stomachs.


An individual of this species was taken off Nova Scotia in 1938, but no other exploitation is known.

IUCN Status

Insufficiently known.