Timing of snowshoe hare winter color swap may leave them exposed in changing climate, study finds
Like many animals in the far north, snowshoe hares change their coats from brown to white each autumn. Come winter, these all-white hares are harder for predators to spot against the snowy landscape, helping ensure their ...
But as global warming reduces snowfall in the region, will the hares' seasonal color swap continue to keep them safe?
Scientists from the University of Florida and Canada are beginning to answer that question. Published in Proceedings of the Royal Society B, Their new study, which used 44 years of data on snowshoe hares in Canada's Yukon Territory, shows that as the region has warmed, hares are waiting longer to turn pure white.
However, the data also suggest that waiting too long can be deadly. The scientists found that hares that were more brown than white in autumn were less likely to survive the winter
"When it comes to the switch from brown to white, which we call molting, timing is everything. We can see in this study that climate change is making it harder for the hares to get that timing just right." said Madan Oli, first author of the study and a professor in the UF/IFAS wildlife ecology and conservation department.
"Hares begin to change color based on environmental cues such as temperature and snow depth, but the change doesn't happen overnight. The whole molting process takes about a month. So, if hares are beginning to molt later in the year, there is a greater chance they will not be fully white by the time their environment is white. These hares are then more vulnerable to predators."
A mismatched snowshoe hare in winter coat in a snow-free landscape in Kluane, Yukon, Canada. Pure white winter coat against snow-free landscape makes snowshoe hares easily detectable by predators, which can reduce their survival during the winter. The study found, however, that hares that wait longer to turn white in autumn face the greatest chance of being eaten by predators during the winter. Credit: Lance Goodwin
Snowshoe hare in winter coat in a snowy landscape in Kluane, Yukon, Canada. Pure white winter coat provides camouflage against snow, which reduces risk of being seen and caught by predators. Credit: Alice Kenney