Strap-toothed beaked whale

Mesoplodon layardii
Other names: 
  • Layard's beaked whale
Maximum length: 
  • Male: 6.1m
  • Female: 6.2m
  • Calf: 2.2m
Maximum weight: 
  • Male: Unknown
  • Female: 1,300kg
  • Calf: Unknown
  • Squid
  • Fish
  • Crustaceans
Estimated population: 
IUCN Listing: 
CITES Appendix: 
CMS Appendix: 
Not Listed

Although rarely seen in the wild, the strap-toothed beaked whale is one of the few species of beaked whale that can be identified at sea because as the name suggests, the adult male has the unusual characteristic of two large tusks that grow up and over the upper jaw. This makes it impossible to open the mouth more than a few inches although this does not seem to affect their health, suggesting that the teeth are not used for catching food, and they may be using a form of suction feeding and targeting smaller species of prey. Females do not have these huge teeth and are therefore more difficult to correctly identify unless sighted in a mixed-sex group.


The strap-toothed beaked whale has a smoothly sloping forehead and slightly rounded melon. The beak is long (one of the longest of the beaked whales), slender and pale in colour and a rather distinctive black patch of colour is found over the eyes and forehead. The body is black with a large white patch covering the top of the body at the front which goes round the neck and under the chest. There is another white patch on the underside of the body below the dorsal fin. Male strap-toothed whales often have white scratches and scars on their bodies, suggesting that they fight with each other. Strap-toothed beaked whales have small, narrow flippers and a small dorsal fin set far back on the body. The flukes are triangular in shape, with pointed tips and no notches.


Strap-toothed beaked whales have been seen floating motionless on the surface, but they do not often let boats get near and are known to sink out of sight when approached. Although not thought to be an acrobatic species, breaching has been recorded by some individuals and as with some other species of beaked whale, they are known to break the waters surface at a steep angle, beak-first.


Strap-toothed beaked whales are known to inhabit cold temperate waters in the southern hemisphere, around the coasts of New Zealand, Australia, Tasmania, South Africa, Namibia, the Falkland Islands, Chile, Argentina and Uruguay. As with other species of beaked whales, threats to strap-toothed beaked whales may include noise pollution, marine debris and climate change. A worldwide population estimate is not known however as this species is the most common species of Mesoplodon known to strand and not thought to be a rare species. The IUCN list the species as Data Deficient.

Distribution map: