Mesoplodon layardii

(Gray, 1865) - Strap-toothed whale

Distinctive Characteristics

Although the body shape of this whale is rather undistinctive, the teeth of adult males are unique. The long tusks emerge from near the middle of the lower jaw and curl backward and inward, extending over the upper jaw, often preventing it from opening more than a few centimetres. How the animals eat with such an arrangement is unknown.

The complex colour-pattern is better-known than that of most species of Mesoplodon, as this species is known from more specimens than any other in the genus. The body is mostly grey or black, sometimes with a purple or brown tinge. Much of the underside is white: around the urogenital opening, between the flippers, on the beak, and in a band of variable width around the head. Variable white or light grey patches tend to be found on the back and sides.

Can be confused with

The unique tusks of adult males of this species will make them identifiable, if seen. Females and subadults will likely be impossible to distinguish from other Mesoplodon species.


Adult females reach lengths of at least 6.2 m and males reach 5.9 m, making this the largest species of Mesoplodon. Length at birth is unknown, but is probably close to 3 m.

Geographical Distribution

Strap-toothed whales may have a continuous distribution in cold temperate waters of the Southern Hemisphere; there have been strandings in South Africa, Australia, Tasmania, New Zealand, Tierra del Fuego, Uruguay, and the Falkland Islands.

Biology and Behaviour

Groups of up to 3 individuals have been seen. These animals are difficult to approach. Strap-toothed whales are commonly stranded, but little has been learned from the few sightings of live animals. They eat squid, and the single stomach examined also contained a piece of algae. Calving appears to occur in spring to summer.


No exploitation of this species has been reported.

IUCN Status

Insufficiently known.