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Tuatara
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Click on photos to enlarge
What are tuatara?
Tuatara means "old spiny back" in Maori.
Tuatara have a primitive body structure that supports the theory that they
are one of the oldest and most un-evolved species, having hardly changed
in the past 220 million years.
Tuatara have a scaly loose skin which is soft to the touch. They have a
variable body temperature which enables them to survive in cold climates.
They live in burrows and are nocturnal, hunting at night just outside
their burrow entrance. They feed on wetas, worms, lizards, millipedes and
small seabirds.
Tuataras are reptiles but they are very different to
lizards, crocodiles and amphibians (frogs, salamanders).
Tuatara differs from lizards, which it superficially resembles, by extra
holes in the skull, bony processes on the ribs, the lack of a copulatory
organ in males, and the presence of a third eye, known as the parietal or
pineal eye, which contains a rudimentary lens and retina and is connected
to the brain by a nerve. However, the whole organ is covered with opaque
scales and the formation of an image would be impossible. Some scientists
believe that this third eye may function as a light sensor, influencing
the amount of time a tuatara spends basking. It is particularly noticeable
in hatchlings which have a patch of white scales at top center of the
skull.
Tuatara teeth, also, are
different from those of other reptiles. They have a single row of teeth in
the lower jaw, and a double row in the upper jaw, the bottom row fitting
neatly between the two upper rows. Little more than serrations of the jaw,
they are not replaced when worn out or damaged, and some old Tuatara are
virtually toothless, chewing their food between smooth jaw bones.
Tuatara facts
hatchling comes out
An
adult can grow up to 24cm in length and weigh about 500 grams. Tuatara
breed only every two to four years. Tuatara lay about a dozen leathery
shelled eggs between October and December. The eggs are burrowed and then
abandoned. After about 12-15 months the eggs hatch, the young using an egg
tooth to break out of their shells. From the start, baby tuatara take care
of themselves, but are very vulnerable to predation. Tuatara mature at
about 13 years old and may live to be 60 years old.
Species of tuatara
There are two species of tuatara. The most
common species is Sphenodon punctatus, the tuatara which is found
on the Northern Islands. It is thought that the Cook Strait Islands
tuatara is a subspecies of the Northern tuatara. S.punctatus has a
brown-white appearance. The second species is the Brothers tuatara
Sphenodon guntheri which is unique to Brothers Island and has an olive
skin with yellow spots.
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For more on tuatara visit
http://www.kcc.org.nz/animals/tuatara.htm
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