The distinguishing character are the very large teeth, 23 cm (9 inches), close in size to those of the strap-toothed whale.

Only strap-toothed whales and spade-toothed whales have longer teeth.

The overall body shape of the strap-toothed whale is fairly typical for a mesoplodont, except for the large size.

Strap-toothed whales' diet consists primarily of squid.

Despite the rather similar dentition, the spade-toothed whale and strap-toothed whale seem to be only distantly related.

This was eventually lumped with the strap-toothed whale, starting as early as an 1878 article by Hector, who never considered the specimen to be specifically distinct.

Strap-toothed whale (M. layardii)

The Strap-toothed whale is distributed in cool temperate waters of the Southern Hemisphere between 30 S and the Antarctic Convergence.

In some cases theses teeth even hinder feeding; in the strap-toothed whale, for example, the teeth curve over the upper jaw, effectively limiting the gape to a few centimeters.

The strap-toothed whale (Mesoplodon layardii), also known as the Layard's beaked whale or the long-toothed whale is a large mesoplodont with some of the most bizarre teeth of any mammal.

The common name was chosen because in life the part of the tooth that protrudes from the gums, (unlike the strap-like teeth of strap-toothed whales) has a shape similar to the tip of a flensing spade as used by 19th-century whalers.

The strap-toothed whale (Mesoplodon layardii), also known as the Layard's beaked whale or the long-toothed whale is a large mesoplodont with some of the most bizarre teeth of any mammal.

The strap-toothed whale (Mesoplodon layardii), also known as the Layard's beaked whale or the long-toothed whale is a large mesoplodont with some of the most bizarre teeth of any mammal.