Climate change is not just a human issue; animals must also adapt. Certain “warm-blooded” creatures are adapting by growing larger beaks, legs, and ears in order to better regulate their body temperatures as the world warms. Sara Ryding of Deakin University in Australia details these changes in a review article published in the journal Trends in Ecology and Evolution on September 7th.
“When climate change is mentioned in the mainstream media, a common question is ‘can humanity overcome this?’ or ‘what technology can solve this?’ It is past time for us to acknowledge that animals must also adjust to these changes, but on a much shorter timescale than would have occurred during the majority of evolutionary time,” Ryding says. “The climate change that we have caused is putting them under tremendous strain, and while some species will adapt, others will not.”
Ryding argues that because climate change is a complicated and multifaceted phenomenon that has been unfolding gradually, it is impossible to attribute the shapeshifting to a single cause. However, because these changes have occurred throughout a broad geographic range and among a diverse variety of species, they share little in common except for climate change.
Strong shapeshifting has been observed in birds in particular. Since 1871, several species of Australian parrot have showed an average rise of 4% – 10% in bill size, which is positively connected with the summer temperature each year. Increased bill size was associated with short-term temperature extremes in cold habitats in North American dark-eyed juncos, a kind of tiny songbird. Additionally, alterations in mammalian species have been recorded. Researchers have seen increases in the tail length of wood mice and in the tail and leg lengths of masked shrews.
“The increases in appendage size we have observed thus far are extremely minor — less than 10% — and thus unlikely to be immediately noticed,” Ryding explains. “However, noticeable appendages like as ears are expected to grow in size — which means we may see a live-action Dumbo in the not-too-distant future.”
Ryding’s next step is to conduct an in-depth investigation of shapeshifting in Australian birds by 3D scanning museum bird specimens from the last century. It will aid her team in determining which birds are experiencing appendage size changes as a result of climate change and why.
“Shapeshifting does not imply that animals are adapting to climate change or that everything is good,” Ryding explains. “It simply implies they are evolving to survive it — but we are unsure of the additional ecological repercussions of these changes, or indeed whether all species are capable of change and survival.”
The Australian Research Council Discovery Project, an Australian Research Council Future Fellowship, and a Natural Sciences and Engineering Research Council of Canada Discovery Grant supported the authors financially.
Materials provided by Cell Press.