Tuatara reptile slices food with 'steak-knife teeth'

Tuatara (c) Marc Jones The researchers filmed the live reptiles at Chester Zoo

Related Stories

New Zealand's tuatara has a unique way of chewing its food, say scientists who have studied its jaws in detail.

This beak-headed reptile uses a "steak-knife sawing motion" as it chews.

This could help explain how the species has continued to adapt to a changing world - and changes in available prey - over more than 200 million years.

A computer model of the tuatara, recreating its jaws as it munched on prey, has revealed that it chews like no other land animal.

The tuatara's lower jaw slides forward "to slice food apart like a saw"

This seems to allow it to "slice up" food that is too big for its mouth.

In their paper in the journal The Anatomical Record, the researchers describe how the teeth of the tuatara's lower jaw close between two upper rows of teeth "before sliding forward to slice food apart like a draw-cut saw".

Nature's best bites

Red-bellied piranha close-up

Lead researcher Marc Jones from University College London said this was very unlike any living lizard or snake, which used "more of a simple opening and closing" motion.

The UK-based researchers were able to observe and film chewing tuataras at Chester Zoo.

Dr Jones and his colleagues from the universities of Hull and York then used this footage to accurately digitise and simulate the creature's characteristic chomp.

Dr Jones said that the "slicing jaws" of the tuatara allowed it to eat a wide range of prey including beetles, spiders, crickets and small lizards.

But he added that this study helped to explain some rather gruesome discoveries in the reptile's habitat.

"People have described finding seabirds with their heads sawn off," he told BBC Nature.

"Tuatara will tend to go for hatchlings if they can, but as far as I can make out [they] do sometimes take small adults.

"[We think] they change their diet seasonally - eating lots more seabirds during the summer."

Close relatives?
Tuatara eating a seabird (c) Paddy Ryan The tuatara's characteristic chew helps it indulge in some grisly eating habits

Although the tuatara looks very much like a lizard, it actually belongs to a group of animals commonly known as beak heads, or Rhynchocephalia in the formal terminology.

The reptile, found wild only in New Zealand, is the last surviving species of its group. Its relatives died out more than 200 million years ago.

At that time, the creatures were spread throughout the globe; scientists have found some the fossilised remains of the tuatara's extinct relatives in the UK.

It is not entirely clear how and why the rest of these ancient reptiles became extinct, but the tuatara's ability to saw up its food could be a secret to its continued survival.

More on This Story

Related Stories

The BBC is not responsible for the content of external Internet sites

More from nature

  • Cardinal fish and ostracodFish filmed spitting 'fireworks'

    Film crew captures ostracods' spectacular defensive lightshow that makes predatory fish spit them out.

  • Arapaima'Locally extinct'

    A giant fish which used to dominate the Amazon river is now absent in many areas

  • DragonflyRapid reactions

    Dragonfly's super quick reactions recorded in slow motion by BBC film-makers

  • Wingless adult male of the midge Belgica antarcticaExtreme survivor

    Antarctic midge's small genome may be an adaptation to its extreme environment

  • Myotis midastactus specimen (previously identified as Myotis simus)Golden discovery

    A bat from Bolivia is described as a new species by scientists

  • Dinosaurs 'shrank' to become birds

    Huge meat-eating, land-living dinosaurs evolved into birds by constantly shrinking for over 50 million years, new research shows.

  • Would we starve without bees?

    Honey bees are under threat, and as pollination significantly contributes to the food we eat, what would we do without them?

  • Eggshells may act like 'sunblock'

    Birds' eggs show adaptations in pigment concentration and thickness to allow the right amount of sun for embryos, scientists say.

  • Female shrimps are more aggressive

    Female snapping shrimps are more aggressive than males when defending their territories despite their smaller claw size, a study shows.

BBC iWonder

  • Honey bee close-upInsect intelligence

    Are honey bees as smart as your sat nav?

  • Tyrannosaurus rex skull (c) Mark Williamson / Science Photo LibraryDinosaur dynasty

    One group of dinosaurs survived and their descendants can be seen all around us today

  • Brown rat cluse upRise of the rodent

    Reports of giant, 'super rats' are filling the headlines. But why are we being overrun by rats?

  • Cuckoo portraitHoliday hotspot

    What makes the UK such an attractive destination for visiting wildlife?

There have been 75 solar eclipses and 167 major volcanic eruptions in my lifetime

Nicole Malliotakis on Twitter comments on the events that have happened since she was born by using our personalised Your Life on Earth interactive infographic.

Get Inspired


More Nature Activities >

Copyright © 2015 BBC. The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.