Mesoplodon layardii (Gray,
English: Layard's beaked whale, Strap-toothed whale
Spanish: Zifio de Layard, ballena picuda de Layard
French: Mésoplodon de Layard, baleine à bec de Layard
Mesoplodon layardii © Wurtz-Artescienza (see links).
M. layardii has a very distinctive black and white pattern
(Pitman, 2009): adults are mainly black with patches of grey and
white that largely occur in the genital area, around the front of
the upper jaw, the lower jaw, throat and chest. There is a grey
blaze from the melon to almost two-thirds of the way to the dorsal
fin. The long tusks emerge in males in the middle of the lower jaw
and curve over the upper jaw, preventing it from opening fully.
This bizarre dentition does not, however, seem to interfere with
(feeding) and prey size (see below). Body size reaches 6.2 m and
body mass up to 1,300 kg (Jefferson et al. 2008). It is possible
that M. layardii could be confused with the spade-toothed
beaked whale M.
traversii, due to their very similar dentition (Van Waerebeek
et al., 2004).
Layard's beaked whale occurs throughout the Southern Ocean; it
has been recorded from Tierra del Fuego and Chubut in Argentina,
Uruguay, the Falkland Islands/lslas Malvinas, Namibia, Cape Province,
Iles Kerguélen, Western Australia, South Australia, Victoria,
New South Wales, Queensland, Tasmania, New Zealand, and Isla Navarino
and the Estrecho de Magallanes in Chile (Rice, 1998). In recent
years, several sightings have been reported from Antarctic waters,
as well as strandings from Macquarie Island and Heard Island (Van
Waerebeek et al., 2004).
Distribution of Mesoplodon layardii (Taylor
et al. 2008; © IUCN; enlarge
map). The species is circumglobal in temperate and sub-Antarctic
southern waters (Pitman, 2002).
The northernmost records of Layard's beaked whale
stem from strandings along the southern Brazilian coast (31-32°S;
Pinedo et al. 2002).
3. Population size
According to Pitman (2002, 2009) it is one of the more widespread
and common beaked whales in the Southern ocean, however some sightings
of M. traversii may have been equivocally attributed to M.
4. Biology and Behaviour
Behaviour: One of the largest of the beaked whales, the
strap-toothed whale is also one of the few Mesoplodon species
that can be readily identified at sea. It may bask at the surface
on calm, sunny days. Generally the animals are hard to approach,
especially in large vessels. Their flukes do not normally show above
the surface at the start of a dive. Limited observations suggest
that strap-toothed whales sink slowly beneath the surface, barely
creating a ripple, then rise and blow again 150-200 m away. Typical
dive time is 10 to 15 minutes (Carwardine, 1995).
Food: The food habits of strap-toothed whales were examined
in detail by Sekiguchi et al. (1996) using stomach contents from
14 whales found stranded on South African and New Zealand coasts.
Although a few unidentified fish otoliths and crustacean remains
were found in two of these stomachs, 24 species of oceanic squids
(some of which occur at great depth) accounted for 94.8% of counted
prey items. Histioteuthis sp. and Taonius pavo were
the predominant prey species. The presence of sub-Antarctic squid
species suggested a concurrent northward migration to South African
waters in late summer/autumn.
Sekiguchi et al. (1996) also compared prey sizes between males with
fully grown strap-teeth and females/immature males without erupted
teeth. Although females/immature males ate longer squids than males,
there was no significant difference in estimated squid weights eaten
by both groups. The presence of fully erupted teeth in adult males,
therefore, did not seem to influence the size of prey ingested,
even though an adult male could only open its jaws about half as
wide as a female.
The seasonality of strandings suggests that this species may migrate
(Taylor et al. 2008, Pitman, 2009).
No exploitation of this species has been reported (Jefferson et
al. 1993; Van Waerebeek et al. 2004).
Range states (Taylor et al. 2008)
Argentina; Australia; Brazil; Chile; Falkland Islands (Malvinas);
French Southern Territories (Kerguélen); Heard Island and
McDonald Islands; New Zealand; South Africa; Uruguay
IUCN status: "Data Deficient". Not listed by CMS. Listed
on CITES Appendix II.
See also recommendations listed in Hucke-Gaete (2000; appendix
8. Sources and further information
Mesoplodon - Beaked whales: Introduction and Sources"
© Boris Culik (2010) Odontocetes.
The toothed whales: "Mesoplodon layardii". UNEP/CMS
Secretariat, Bonn, Germany. http://www.cms.int/reports/small_cetaceans/index.htm
© Illustrations by Maurizio Würtz, Artescienza.
© Maps by IUCN