There have also been reported changes in mammalian species, including tail length increases in wood mice, and tail and leg size increases in masked shrews. Animals can divert blood flow to non-insulated appendages such as beaks, ears and legs to shed excess body heat.
It has long been that temperature can lead to patterns in overall body shape. According to a 19th century zoological law known as Allen’s rule, animals that live close to the equator tend to have larger extremities, so as to radiate heat, while animals close to the poles need to retain heat so have smaller extremities.
Climate change adaptation is often discussed as a human problem, but animals are also having to adapt over a far shorter timescale than has occurred throughout evolutionary time, Ms Ryding says.
While the increases in appendage size seen so far are quite small – less than 10 per cent – prominent appendages such as ears are predicted to increase, says Ms Ryding.
Ms Ryding started her research two years ago with collaborators at the Australian National University and Brock University in Canada, who looked at how bird beaks are used in regulating body temperature.
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