A red squirrel in Cairngorms National Park, Scotland

A red squirrel in Cairngorms National Park, Scotland

For the red squirrel, Cairngorms National Park is something of a refuge. This vast Scottish wilderness saw, like other parts of the British Isles, a steep decline in the red squirrel population after humans introduced the non-native grey squirrel to the area in the late 1800s. The greys can eat a wider variety of food and brought with them diseases to which the red squirrels were susceptible. But luckily for the red squirrel, pine martens, a weasel-like critter, find grey squirrels especially tasty, and as a result, the red squirrel population here is on the rise again.

Nevertheless, the red squirrel’s not yet out of the woods, as it were. Scientists recently discovered that a significant portion of the UK’s population of red squirrels carries a form of leprosy. Not only is this bad news for the red squirrel, but health officials had been under the impression that leprosy had died out in the UK centuries ago. They stress that the infection poses little - if any - threat to humans, but it’s another difficult challenge for the red squirrel. Now if only the pine marten could solve that problem, too.