Why do arctic foxes change colour in the summer?
21st Aug 2023
Authored by David Traub, an Environmental Management and Sustainability student with special interests in nature conservation and scientific communications.
Come to Wildwood Devon and you’ll definitely want to stop in and see our Arctic foxes. Miska, our male fox, came to us in 2021 and has been a popular attraction ever since. He was recently joined by Aurora, a female, who came to us just this year. While there are no breeding plans for them just yet, things may change in the future. But you may be surprised when you see them for the first time, depending on what time of the year you visit!
Canine or chameleon?
Photo: Miska moulting his winter coat
Arctic foxes, or Vulpes lagopus, are incredibly adaptive species. They survive in some of the harshest environments on earth, across the Arctic tundras and at one time, the Scottish North. Unlike many of their Arctic counterparts, they do so without the need to hibernate during the scarcest months. Arctic foxes are designed for their environment from head to toe, and among the more obvious of these adaptations are the fluctuations they undertake with their coats. When the landscape of its natural home is dominated by snow, the Arctic fox sports its trademark thick and white winter coat.
The warmest of any Arctic animal, this coat helps them to withstand temperatures as low as -70° Celsius. However, as the temperatures change and the snow melts, so does the coat. It thins out to better regulate body heat, and goes from a brilliant white to muddy brown, black or red. This change of colour allows the fox to blend in with the changing environment, which it uses along with its quickness and keen sense of hearing to avoid threats.
Built for this!
However, regulating its coat is just one trick up the fox’s sleeve. Here, head to toe is more than just a phrase! The Arctic fox sports thick extra fur under its padded paws, which not only keeps its toes warm, but also regulates heat exchange between the paws and the ground underfoot. In general, the paws are always kept at a lower temperature than the body, and through a system known as counter current heat exchange whereby blood vessels in the extremities reheat blood as it returns to the body, the Arctic fox can stay nice and cosy. Many other animals such as dogs and penguins share a similar mechanism. Combine this with its thick layer of fat, its dark black skin, its relatively stocky frame, and its omnivorous ability, and it’s clear that the Arctic fox is built for its frozen environment.
Foxes in the future
Luckily, Arctic foxes number in the hundreds of thousands in the wild, moving across the northern most parts of the world’s tundras following their prey or looking for suitable breeding spaces. Once threatened by the fur trade, strong protection laws and their hardy nature have restored their conservation status to “least concern” as ranked by the International Union for Conservation of Nature (IUCN) Red List of Threatened Species.
Unfortunately, they are still threatened by the drastically changing polar environment in which they thrive. In the Intergovernmental Panel on Climate Change’s (IPCC) latest report, it was stated that Arctic surface temperatures had increased by more than double the global average over the last since the early 1990s. Melting permafrost threatens their food supply, decreasing ice cover and rising sea levels claim their habitat, and the larger red fox is pushing further north into their territory.
To end on a positive note, look up videos of the Arctic fox snow diving to catch lemmings – you can thank us later!
For more information on Wildwood Trust and its mission to conserve and protect British wildlife, click here.