Warming threatens gender-bending reptile
By Regina and Douglas Haggo
The Hamilton Spectator
(Dec 9, 2006)
The New Zealand five-cent coin was removed from circulation this year. The tuatara, a rare reptile whose image appears on the coin, could soon follow it into extinction.
The tuatara is found only in New Zealand, where it's known as the living fossil.
All the other species in the Sphenodontia order disappeared about 60 million years ago.
The tuatara may have survived whatever killed the dinosaurs, but it could be wiped out by global warming.
That's because the sex of a tuatara is determined by the incubation temperature of its egg, where it spends 11 to 16 months before hatching.
As the temperature rises, so does the proportion of males. Already there's a shortage of breeding females, which apparently mate every two to four years.
Experiments have shown that the proportion of males reaches 100 per cent at 22 C, Nicky Nelson of Victoria University of Wellington told National Geographic.
Tuatara, which can live more than 100 years, thrived throughout New Zealand before they were nearly killed off by dogs, cats, rats and other mammals that arrived with humans. Now the reptile can be found only on about 30 small islands.
Scientists are trying to help the tuatara sidestep extinction by collecting eggs from some islands and putting them in incubators.
"We can dial in whatever sex we like," Nelson said.
Further Story
http://www.sanctuary.org.nz/whatsnew/stori...se2Dec2005.html
Tuatara arriving by helicopter
Update to above story
http://www.sanctuary.org.nz/whatsnew/stori...e15Dec2005.html
More Pics
http://www.ryanphotographic.com/tuatara.htm
By Regina and Douglas Haggo
The Hamilton Spectator
(Dec 9, 2006)
The New Zealand five-cent coin was removed from circulation this year. The tuatara, a rare reptile whose image appears on the coin, could soon follow it into extinction.
The tuatara is found only in New Zealand, where it's known as the living fossil.
All the other species in the Sphenodontia order disappeared about 60 million years ago.
The tuatara may have survived whatever killed the dinosaurs, but it could be wiped out by global warming.
That's because the sex of a tuatara is determined by the incubation temperature of its egg, where it spends 11 to 16 months before hatching.
As the temperature rises, so does the proportion of males. Already there's a shortage of breeding females, which apparently mate every two to four years.
Experiments have shown that the proportion of males reaches 100 per cent at 22 C, Nicky Nelson of Victoria University of Wellington told National Geographic.
Tuatara, which can live more than 100 years, thrived throughout New Zealand before they were nearly killed off by dogs, cats, rats and other mammals that arrived with humans. Now the reptile can be found only on about 30 small islands.
Scientists are trying to help the tuatara sidestep extinction by collecting eggs from some islands and putting them in incubators.
"We can dial in whatever sex we like," Nelson said.
Further Story
http://www.sanctuary.org.nz/whatsnew/stori...se2Dec2005.html
Tuatara arriving by helicopter
Update to above story
http://www.sanctuary.org.nz/whatsnew/stori...e15Dec2005.html
More Pics
http://www.ryanphotographic.com/tuatara.htm