Translator’s Remarks:
This is an article regarding the impact of global warming on poikilotherms (ectotherms). The original text is quite long and originates from the “Scientific American” website; this version has been slightly abridged.
While humans continuously report on the impacts of climate change on humanity, other organisms in nature are also being affected by the climate. Perhaps, other creatures in nature are the greatest victims. Regardless, for ourselves, for nature, for the Earth, and for future generations, we should all consciously work to reduce the greenhouse effect. If everyone saves just a little bit, the world will have more greenery and more blue skies!
By Robert Goodier
A new study warns that cold-blooded land animals, such as tropical lizards and insects, may wither and die as the world warms. “Cold-blooded” is the layman’s term for poikilotherms (ectotherms), whose body temperature changes with the surrounding environment rather than being internally regulated like homeotherms (endotherms). They are able to thrive in environments with temperatures ranging from 68 to 104 degrees Fahrenheit (20 to 40 degrees Celsius) and are generally unaffected by overheating. However, as the globe warms, researchers warn that they may be forced to stay trapped in sweltering burrows and thickets, leaving them with almost no time to feed, find mates, or rear their offspring.
“Our models suggest that the habitats for many reptiles will become very narrow,” says Rick Shine, an evolutionary biologist at the University of Sydney in Australia. “They are likely to encounter trouble due to climate change,” he added, noting that their range of activity will be limited to the shrinking shade beneath forests and near bodies of water where they can cool down.
The resulting loss of tropical ectotherms could be “catastrophic.” Shine found that this situation could destroy entire ecosystems, from food webs to pollination. The reason: ectotherms, ranging from insects to top predators like snakes and crocodiles, occupy critical positions in the food chain, and their loss would have a significant impact, Shine says.
“Shade is extremely important to them,” Porter speculates. They must rely on water and dense vegetation to stay cool; they may have already begun migrating as the climate changes, and they must maintain slow metabolic rates. In hot seasons, large animals cool down more slowly than smaller ones, so “it is impossible for large animals to have high metabolic rates like ours,” he says, “otherwise they would cook themselves.” Additionally, some paleontologists believe that dinosaurs were endotherms—that is, they were able to regulate their body temperature internally just as we do.
Original Text:
Warming World Too Hot for the Cold-Blooded?
To combat overheating as climate warms
By Robert GoodierA new study warns that cold-blooded land animals like lizards and insects in the tropics may wither as the world warms. “Cold-blooded” is the layman’s term for ectotherms—animals whose body temperature is contingent on the surrounding environment, rather than internally regulated like that of warm-blooded creatures. They thrive in temperatures ranging from 68 degrees to 104 degrees Fahrenheit (20 to 40 degrees Celsius), above which they overheat. As the globe warms, researchers warn they may be forced to swelter in burrows and under bushes with little time to eat, find mates or rear young.
“Our models suggest that for many reptiles, the room to move may be pretty small,” says Rick Shine, an evolutionary biologist at the University of Sydney in Australia and co-author of the study published recently in Proceedings of the National Academy of Sciences, USA. “They are likely to be in trouble with climate change,” he adds, noting they will be confined to shrinking shady patches under disappearing forest canopy and in bodies of water where they can cool off.
The resultant loss of tropical ectotherms could be “catastrophic,” Shine says, noting that it could tear apart entire ecosystems from food webs to pollination. The reason: ectotherms range from food sources like insects to top predators like snakes and crocodiles, the loss of which would have “major flow-on effects,” Shine says.
“Shade would have been extremely important for them,” Porter says. They must have been tied to water and dense vegetation to keep cool, they may have migrated with changing seasons, and they must have had lower metabolisms, he speculates. Large animals cool more slowly than smaller ones in hot climates, so “The big animals could not possibly have had a high metabolic rate like we do,” he says, “or they would have cooked themselves.” Alternatively, some paleontologists believe the dinosaurs were endotherms – that is, they regulated their body heat internally like we do.