Feb. 17, 2009 -- Commonly known as being cold-blooded and in need of some sunshine, the world's ectotherms may be struggling to keep cool in the future. The finding raises concerns about how animals that regulate their body heat using air temperature will cope in a warmer world predicted by climate change. Writing in this week's issue of Proceedings of the National Academy of Sciences, a team of Australian and U.S. researchers say the impact of climate change on ectotherms will depend on how global warming-induced changes in habitat alter the ability to access shade. Another factor will be the animals' capacity to alter the seasonal timing of their activity and reproduction. Lead author Michael Kearney, of the University of Melbourne's Department of Zoology, said the results of their modeling are counter-intuitive. "The majority of the world's animals are cold-blooded," Kearney said. "So if it gets warmer you would think it might be better for them." Related Content: However, Kearney said using modeling that combines spatial data on climate, geography and vegetation, with behavioral models they were able to determine whether the priority of thermoregulating ectotherms such as reptiles and insects was to keep warm or stay cool. "What we've found is that for a large fraction of the planet's animals their main priority is to thermoregulate to stay cool," Kearney said, "and global warming is going to make keeping cool harder." Not only will air temperatures be higher, he said, but the availability of habitat in which to shade could be altered. For the study, Warren Porter, of the University of Wisconsin's Department of Zoology, and the University of Sydney's Rick Shine studied the effects of climate change on a small Australian lizard known as the heath monitor (Varanus rosenbergi). The modeling was based on the lizard living in three different climate zones -- temperate coastal, Melbourne; arid continental, Alice Springs; and tropical coastal, Darwin. The consequences of three different behaviors -- sitting in full sun, sitting in full shade and moving in and out of shade to maintain a preferred body temperature -- in those three zones was then mapped. Kearney said the big surprise of their work was to find that so-called "cold-blooded animals" were more focused on keeping cool than on warming up. Get More NewsSpiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates.Oldest Hebrew Writing Possibly FoundAncient inscriptions on a 3,000-year-old pottery shard could make history.Rare, Prehistoric-Age Reptile Found in N.Z.A tuatara has been spotted on the New Zealand mainland for the first time in 200 years.Iceman Has No Living RelativesOetzi, the 5,300 year-old frozen mummy, left no living genetic legacy.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.It's Official: People Are Warming the PolesHumans are conclusively to blame for polar warming, say scientists.Eight-Armed Animal Preceded DinosaursWhat may be one of Earth's first animals was no bigger than a coaster and had eight arms.Phoenicians Live on in People's GenesOne in 17 Mediterranean men may be descended from ancient Phoenicians.Pesticides, Fertilizers Linked to Frog DeclineA pesticide is found to promote parasites among amphibians.Hubble Telescope Taking Photos AgainThe Hubble Space Telescope is once again snapping stunning photos of the universe.Andean Mummy Hairs Show Hallucinogen UseScientists find direct evidence of hallucinogenic drug use among ancient Andeans.Opals on Mars Reveal Planet's Long Wet PastOpals found on Mars suggest the planet has been wet for much longer. |
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