The discovery came during routine maintenance work, when conservation officer Bernard Smith found the 8cm-long hatchling in an area where nests had been discovered. The animal is thought to be around one month old and is likely to have hatched from eggs laid around 16 months ago.
"This is an extremely significant discovery" said conservation manager Raewyn Empson.
"We knew our tuatara were laying eggs, but we didn't dare hope to find any young. Monitoring the nests 24/7 just wasn't practical. We certainly didn't expect to see them so soon and perhaps not until they were adults. We are all absolutely thrilled with this discovery. It means we have successfully re-established a breeding population back on the mainland, which is a massive breakthrough for New Zealand conservation. He is unlikely to be the only baby to have hatched this season, but seeing him was an incredible fluke".
The youngster 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 morepork (native owl); kingfisher and weka (New Zealand's endemic flightless rail).
"Like all the wildlife living here, he'll just have to take his chances" said Ms Empson
"However, hatching within the safety of of mammal-proof fence has already given him a far better chance of survival than he would get outside our mammal-proof fence. Out there, the survival rate would be almost zero".
Tuatara are the only extant members of the Order Sphenodontia and endemic to New Zealand. Every other species in this Order became extinct about 60 million years ago, leading scientists to refer to tuatara as ‘living fossils’.
Tuatara are thought to have been extinct as a breeding population on the three main islands of New Zealand for around 200 years. They were wiped out, primarily, by the kiore (Pacific rat) which arrived with the first Polynesian settlers around 700 years ago.
In 2005, 70 animals were translocated to the Karori sanctuary, New Zealand's first fenced mainland conservation project from one of their last offshore island refuges - Takapourewa/Stephens Island in Cook Strait, with the blessing of the animals' Maori kaitiaki (guardians) Ngati Koata. A further 130 animals were traslocated two years later. These two transfers marked a major breakthrough in re-establishing this species in the wild on mainland New Zealand. It has also made the species a lot more visible to the public.
In late 2008, staff identified a number of nest sites. At least two contained clutches of leathery, ping-pong ball-sized eggs. The eggs were immediately covered up again to avoid disturbing their incubation. Although only four eggs were unearthed, it is likely that there are more in the nest – an average clutch contains around ten.
Other than guarding the nest for a few days after laying to prevent other females digging the nest up, that is the end of maternal responsibility. All being well, the tuatara could hatch any time between now and March. The hatchlings will break out of the eggs using a special egg-tooth that will fall off after about two weeks. For the first six months or so the legendary ‘third eye’ for which the tuatara is most famous will be visible as a white patch on the forehead. This too will disappear as the tuatara grows.
As with some other reptiles, soil temperature will determine the animals’ gender. Warm soil (over 21 degrees) results in males, and cool soil (under 21 degrees) females.
ZEALANDIA: The Karori Sanctuary Experience was recently acknowledged as one of Australasia’s top 25 ecological restoration projects by the Australia-based EMR Journal.
Additional information on tuatara breeding behaviour
o Tuatara breed only every two to four years.
o Unlike lizards, the male tuatara does not have a pe_nis. He mounts the female and passes sperm straight from his cloaca to hers (the cloaca is a small opening that serves the intestinal, urinary and genital tracts of certain reptiles and birds).
o Female tuatara become fertile at about 13 years age.
o She will carry up to 12 eggs for nine months.
o The leathery eggs will be laid between October and December; buried and abandoned.
o After about 12-15 months the eggs hatch, the young using an egg tooth to break out of their shells. From day one, tuatara take care of themselves.
o Like alligators, crocodiles and turtles, a tuatara’s gender is determined by the temperature at which it was incubated in the egg. Eggs laid in warm soil hatch into males, those in cool soil hatch into females, and those in moderate or oscillating temperatures into a mix of both.
o Tuatara are born with a legendary ‘third eye’ (actually a light-sensitive pineal gland) on the top of their skulls. This slowly closes over as they mature.
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