Layard's beaked whale - Mesoplodon layardii

Taxonomy & Nomenclature

Scientific Name Mesoplodon layardii
Author (Gray, 1865)
Taxonomic Rank Species
Taxonomic # 180516
Common Names English: Strap-toothed Whale
English: Layard's beaked whale
English: strap-toothed beaked whale
Current Standing valid
Taxonomic Parents Kingdom: Animalia
  Phylum: Chordata
    Subphylum: Vertebrata
      Class: Mammalia
        Subclass: Theria
          Infraclass: Eutheria
            Order: Cetacea
              Suborder: Odontoceti
                Family: Hyperoodontidae
                  Genus: Mesoplodon
Taxonomic Children
Synonyms (since 1950)

Taxonomic data is courtesy of the Integrated Taxonomic Information System (ITIS)
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Physical Description / Field Identification

Although the body shape of this whale is not very distinctive, 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 centimeters. How the animals eat with such an arrangement is unknown.

The complex color pattern is better-known than that of most mesoplodonts, as this species is known from more specimens than any other in the genus. The body is mostly gray 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 gray patches tend to be found on the back and sides.

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

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 mesoplodonts.


Strap-toothed beaked 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. The seasonality of strandings suggests that this species may migrate.

Ecology and Behavior

Groups of up to three 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. Calving appears to occur in spring to summer.

Feeding and Prey

They eat squid, and the single stomach examined also contained a piece of algae.

Threats and Status

There is little information available on the status of the strap-toothed whale. Currently, this species is ‘Data Deficient’ (IUCN) and ‘Not Listed’ (ESA).



Dalebout, M.L. 2002. Species identity, genetic diversity, and molecular systematic relationships among the Ziphiidae (beaked whales). Ph.D. dissertation, University of Auckland, New Zealand.

Mead, J.G. 1989. Beaked whales of the genus Mesoplodon. pp. 349-430 in S.H. Ridgway and R. Harrison, eds. Handbook of marine mammals, Vol. 4: River dolphins and the larger toothed whales. Academic Press.

Pitman, R.L. 2002. Mesoplodont whales Mesoplodon spp. pp. 738-742 in W.F. Perrin, B. Würsig and J.G.M. Thewissen, eds. Encyclopedia of marine mammals. Academic Press.

ITIS TSN180516
Status - ESA, U.S. FWS
Status - Red List, IUCN
    LC (Global)
#records (spatial)34
#records (non-spatial)0
Year1912 - 2024
Latitude-60.45 - -22.87
Longitude-65.90 - 172.65
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