Mammals
Strap-Toothed Whale
Mesoplodon layardii · also called strap-toothed whales, Layard's beaked whale
Rarely seen alive, a male strap-toothed whale carries a pair of teeth so extraordinarily long they curl right over the upper jaw, an anatomical extreme so pronounced it can partially limit how wide the animal is even able to open its own mouth.
Overview
The strap-toothed whale, Mesoplodon layardii, is the largest species within its genus, native to cold circumpolar waters across the Southern Hemisphere, including areas around New Zealand, southern Australia, and southern South America. Its extraordinarily long, curling male teeth, reliance on suction feeding despite a restricted gape, and considerable size relative to its close relatives make it one of the more anatomically extreme and genuinely fascinating members of the beaked whale family.
Teeth so long they get in the way
Few animals grow a feature as functionally costly as the strap-toothed whale’s male teeth, curling so far over the jaw that they can restrict the very mouth opening the whale needs to feed, a trade-off nature apparently judged worth making for competitive advantage.
Status
Least Concern based on available evidence, present across suitable cold Southern Hemisphere ocean habitat, though its elusive lifestyle makes precise population assessment genuinely difficult.
Strap-Toothed Whale: common questions
Why do male strap-toothed whales have such unusual teeth?
A male of this species grows a pair of extraordinarily long teeth that curl over the upper jaw, an extreme growth pattern that can partially restrict how widely the mouth is able to open as the animal matures, a genuinely unusual trade-off likely tied to competitive display among males.
How does the strap-toothed whale eat if its mouth can't fully open?
Despite the potential restriction on mouth opening caused by its long teeth, this species is believed to capture prey largely through powerful suction feeding, drawing squid into the mouth rather than relying on a wide gape to seize prey directly, an adaptation shared with several other beaked whale species.
How big is the strap-toothed whale compared to its relatives?
This species is the largest member of its genus, noticeably bigger than several of its close beaked whale relatives found across similar Southern Hemisphere waters, making size one of the clearer distinguishing features when comparing it against related Mesoplodon species.
Where does the strap-toothed whale live?
This species occupies cold circumpolar waters across the Southern Hemisphere, including areas around New Zealand, southern Australia, and southern South America, a range shared broadly with several other Southern Hemisphere beaked whale and dolphin species.