Wednesday, January 28, 2009

Hibernating Species Less Likely to Go Extinct?

The best way to survive the ill-effects of climate change and pollution may be to simply sleep through it.

According to a new study published in The American Naturalist, mammals that hibernate or that hide in burrows are less likely to turn up on an endangered species list. The study's authors believe that the ability of such "sleep-or-hide" animals to buffer themselves from changing environments may help them avoid extinction.

The idea that sleepers and hiders may have a survival advantage first arose from a study of the fossil record conducted by Dr. Lee Hsiang Liow of the University of Oslo. That study found that sleep-or-hide mammals seem to last longer as species than other mammals.

In this latest study, Liow and colleagues from the Universities of Oslo and Helsinki wanted to see if this trend holds for mammals living today.

Using a database of over 4,500 living mammal species, Liow and his team identified 443 mammals that exhibit at least one sleep-or-hide behavior. Their list includes tunneling and burrowing animals like moles and chipmunks, as well as animals that can periodically lower metabolic rates like squirrels, bats and bears.

The sleep-or-hide list was then compared with "Red List" of threatened species compiled by the International Union for Conservation of Nature. As the researchers suspected, sleep-or-hide species are less likely appear in any of the IUCN's high-risk categories. The pattern holds even under controls for other traits that may influence extinction rates, such as body size (smaller animals generally have lower extinction rates) and geographic distribution.

There are some interesting implications here.

Potentially, if the Lystrosaurs were burrowers as I believe is suspected could they and other species that were estivators/hibernators or had low metabolic requirements - ie could handle long fasts like crocs can - simply survived because they had lower, much lower constant energy intake requirements. Munch up through the lesser nasty season and then dig in. Or wait it out (if you are croc esque).

That would turn on its ear the idea that endothermy had anything to do with the PT Extinction. Since the gorgons had turbinates, IMNSHO, that was the case anyways, but...

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