Animals are Evolving to Cope with Climate Change

A new study, published by Deakin University in Australia, found that birds, in particular, are developing larger beaks, legs and ears to better regulate their body temperatures.

Rather than thinking of climate change as an issue that just humans must adapt to, bird researcher Sara Ryding says we need to realize it impacts other species too.

“It’s high time we recognized that animals also have to adapt to these changes, but this is occurring over a far shorter timescale than would have occurred through most of evolutionary time.”

Climate change is putting pressure on animals to adapt at an increasing rate, and though some may be able to, others may not, she warns.

According to a report published by The Conversation, global warming presents a major challenge for animals that must maintain a constant body temperature.

Animals are dealing with global warming in various ways. Some move to cooler areas, such as closer to the poles or to higher ground. Some change the timing of key life events such as breeding and migration, so they take place at cooler times. And others evolve to change their body size to cool down more quickly.

This study comes after decades of observing how animals adapt to global warming.

Adhering to Allen’s rule

According to Allen’s rule, animals use their appendages to regulate their internal temperature; African elephants, for example, pump warm blood to their large ears, which then flutter to disperse the heat. The beaks of birds perform a similar function – blood flow can be diverted to the bill when the bird is hot.

This heat-dispersing function is depicted in the thermal image of a king parrot below, which shows the beak is warmer than the rest of the body.

Thermal image of a king parrot, showing that the beak is warmer than the rest of the body.

All this means there are advantages to bigger appendages in warmer environments. In fact, as far back as the 1870s, American zoologist Joel Allen noted in colder climates, warm-blooded animals – also known as endotherms – tended to have smaller appendages while those in warmer climates tend to have larger ones.

This pattern became known as Allen’s rule, which has since been supported by studies of birds and mammals.

Biological patterns such as Allen’s rule can also help make predictions about how animals will evolve as the climate warms. Our research set out to find examples of animal shape-shifting over the past century, consistent with climatic warming and Allen’s rule.

Animals are adapting to both warmer and colder climates

This rapid form of evolutionary change has produced a 4-10 per cent increase in the size of bills in Australian parrots since 1871 — a number that positively correlates to the increasing annual temperature in the country.

A small songbird named a North American dark-eyed junco also appears to be evolving at a heightened rate, the study outlines. A link has been noticed between their increased bill size and short-term temperature extremes in cold environments.

Wood mice are growing longer tails to help them cope with the heat

Researchers involved in the study detail the increasing tail lengths of wood mice, and leg size increases of masked shrews.

These findings build on earlier research detailing how the world’s plants and animals are adapting in order to survive in harsher climates, brought on by the effects of climate change.

Not all animals will learn to adapt

Genetic migration changes in salmon are thought to have created earlier migration patterns, leading to greater survival rates.

Studies have found evolutionary changes in plants such as thyme have made the herbs more resistant to warmer climates.

In the animal kingdom, tawny owls are known to be turning browner as the regions they occupy see less and less snow, and as such less need for their white coats.

Less snow means Tawny owls are becoming browner.

However, Ryding writes that these evolutionary changes are not a sign animals are coping well with climate change.

“It just means they are evolving to survive it,” she says, warning that “we’re not sure what the other ecological consequences of these changes are, or indeed that all species are capable of changing and surviving.”

For each adaptation though, there may be many more species at risk.

Over 30 per cent of tree species are threatened by extinction; Komodo dragons have recently been moved from the vulnerable species list to the endangered species list; and avocados, vanilla and native orchid species are all amongst a list of wild crops that are currently facing extinction.