On a scattering of small islands off the north coast of New Zealand, members of an ancient reptile species are currently scuttling around, oblivious to the impending doom that researchers predict for them.
Like many reptiles, the tuatara’s sex is determined by the nest temperature while the embryo is developing; now researchers have used computer modeling to determine that global warming could raise island temperatures to the extent that the nests will produce only male hatchlings by 2085. As temperatures tick upwards, the male tuatara will be increasingly desperate and dateless [Australian Broadcasting Corporation].
The study, which was published in Proceedings of the Royal Society B [subscription required], could be the model for studies of lizards and marine turtles with similar reproductive systems. “Since the mid 1990s, people have been talking about the vulnerability of reptiles to climate change because they have temperature-dependent sex determination. But no one has been able to model it in this type of complexity before,” says research leader Nicola Mitchell of the University of Western Australia in Perth [Nature News].
These “living fossils” are the only surviving members of the Sphenodontian family, which roamed the Earth about 200 million years ago [LiveScience]. The tuataras survived other violent climate upheavals, but researchers say that in previous eras the species had a larger range and could relocate to areas with better climates when times got tough. Now that the tuataras are confined to a series of small islands they would need human assistance to relocate.
But researchers did come up with another solution, suggesting that the tuataras could be saved in their natural habitat if conservationists provided nest sites with artificial shade once the embryos have started to develop. “Tuatara are ancient animals. Their ancestors were scurrying around the feet of dinosaurs. It would be a great shame to lose them,” Michael Kearney, of the University of Melbourne, said [The Times].
Image: Nicky Nelson, Victoria University
July 2nd, 2008 at 6:17 pm
[...] See more DISCOVER coverage of the tuatara here. [...]
July 3rd, 2008 at 3:17 am
Wouldn’t the females that did hatch carry on whatever genetic quirk let them hatch under normally adverse conditions to their offspring? If that was the case wouldn’t genetic lines of these reptiles develop that flourish under the warmer temperatures while the other lines die off?
July 3rd, 2008 at 9:34 am
“Wouldn’t the females that did hatch carry on whatever genetic quirk let them hatch under normally adverse conditions to their offspring? If that was the case wouldn’t genetic lines of these reptiles develop that flourish under the warmer temperatures while the other lines die off?”
<Morbo>Evolution does not work that way!</Morbo>
Seriously though, it wouldn’t be genetic quirk that causes females to be born. The probability of being born female among reptiles is related to the temperature at which the eggs develop. It’s possible though unlikely that some mutations could occur which cause some reptiles’ eggs’ sex to no longer be related to temperature but given that that’s been happening for millions of years, the sudden shift could take the species off guard and screw them over.
Unless I’m taking out of my ass, which is entirely possible.
July 3rd, 2008 at 10:01 pm
[...] Global Warming Could Bring Single-Sex Doom to Ancient Reptile On a scattering of small islands off the north coast of New Zealand, members of an ancient reptile species are currently scuttling around, oblivious to the impending doom that researchers predict for them. … [...]
July 4th, 2008 at 1:28 pm
maybe that was the reason why ALL saurus disappeared.
July 8th, 2008 at 5:59 am
“maybe that was the reason why ALL saurus disappeared”
What? You don’t like geological evidence for the ‘meteor theory’? :)
July 11th, 2008 at 11:04 am
[...] Find out more [...]
December 21st, 2008 at 2:25 pm
There were mammals, insects, fish. They didn´t disappear because of the meteorite.
Did they?????