For humans, adapting to (适应) climate change will mostly be a matter of technology. More air conditioning, better-designed houses and bigger flood defenses may help reduce the effects of a warmer world. However, animals will have to rely on changing their bodies or their behaviour. 

In a study done by Trends in Ecology & Evolution, a team led by Sara Ryding, a PhD at Deakin University, in Australia, shows that is already happening. And climate change is already changing the bodies of many animal species, giving them bigger beaks (鸟喙), limbs and ears. 

In some species of Australian parrot, for example, beak size has increased by between 4% and 10% since 1871. All that is nicely in line with evolutionary theory (进化论). "Allen's rule", named for Joel Asaph Allen, who suggested it in 1877, holds that warm-blooded animals in hot places tend to have larger appendages (附肢) than those in mild regions.

Such increase in an animal's surface area helps it release (释放) extra heat. For example, being richly gifted with blood vessels, and not covered by feathers, beaks make an ideal place for birds to release heat.

It seems clear that the world of the future is not just going to be hotter than humans are used to. These animals living in it will look different, too. Studying a larger range of animals will help figure out what is exactly happening. Much of Ms Ryding's data is about birds, however, with less information available for other animals.