Saturday, March 21, 2009

Welcome, baby tuatara



Driving home from work last night thinking my usual happy Friday night thoughts, I was distracted to listen to a radio interview about a baby tuatara that has been born on mainland New Zealand, the first confirmed birth in over 200 years. One of the few things I know about tuatara is that they are like crocodiles, alligators and turtles in that their sex is determined by the temperaturs of the soil in which they are incubated. Males comes from warm soil (males aways need to be more pampered so that bit is easy to remember), females from cool soil, and
soil where the temperature changes produces both males and females.

I’d say the temperature in Wellington soil would change quite a bit in the 12-15 months it takes for the eggs to hatch, and they didn’t say what gender this little blighter is. I’ll refer to him as a he.


Here's the new arrival - look male or female?

He was born in New Zealand’s first fenced mainland conservation sanctuary. In 2005, 70 animals were taken there from offshore island refuges. Another 130 arrived two years later.

So what’s taken them so long to reproduce?

Well, first of all they don’t reach sexual maturity until they’re 15 – 20 and then will only breed every two to four years. Then, the female will carry the eggs (up to 12) for 9 months. When she lays her eggs she buries them, hangs around for a few days to make sure other females don’t dig up the nest, then wanders off to carry on with life. The eggs have to survive for over a year before hatching. Luckily the young have an eye tooth for freeing themselves from their eggs. Then they are on their own.

And their mating habits sound a bit hit and miss. A male sits outside a burrow and when a female walks past he will circle her. If she is interested they will mate. Surely there is something else going on there but not according to what I’ve read.

The tuatara is a reptile, although it looks more like a lizard. They are very ancient – the only survivors of a large group of reptiles that roamed the earth at the same time as dinosaurs. It hasn't changed its form much in over 225 million years! Its relatives died out about 60 million years ago. How special is that? Another thing that makes them so special to us is that they only found here in New Zealand.



Tuatara is a Maori word meaning "peaks on the back". It is easy to see why.

I think of them as beautiful little prehistoric monsters. The male tuatara grows to an average length of 60cm (23.5 inches), weighs around 1kg (2.2 pounds) and has an obvious crest of spines along its back. The female tuatara is smaller; they grow to an average length of 50cm (19.5
inches) and weigh about 550grams (1.2 pounds). There’s nothing monster-ish about their eating habits though. They have teeth designed for crunching their way through tough backed insects, like the native weta.

The recently born baby was caught briefly for a photoshoot and then released back in the spot he was found. He faces a tough journey to adulthood. Not only will he have to run the gauntlet of cannibalistic adult tuatara, he would also make a tasty snack for species like my beloved ruru (native owl) and kingfisher.

A spokesperson for the sanctuary said, "Like all the wildlife living here, he'll just have to take his chances."

Good luck, beautiful little monster!


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