Wednesday, 31 December 2014

Artic Fox

This month’s creature is small, furry, cute, and snuggly warm - considering where it lives. It is the arctic fox, also known as white fox, polar fox or snow fox. It may be a cute one but it is also a killer as it preys on small animals like lemmings, voles, ringed seal pups, fish and seabirds; do not underestimate it!

The arctic fox (Vulpes lagopus meaning “true fox”) belongs to the Vulpes of the Vulpini tribe, which is part of the subfamily Caninae of Canidae. That is a whole bunch of biology talk basically saying it is related to dogs, wolves, jackals, coyotes, etc… They are about the size of your average fox. Average males being 55cm (22in) head and body where female are 52cm (20in). They both have about 30cm (12in) long tails and stand 25 to 30cm (9.8 to 11.8in). Males weigh about 3.5kg (7.7lb) and females 2.9kg (6.4lb): these measurements are important.
Now with all the science stuff out of the way, on to the cute and cool stuff. Arctic foxes live in some of the most extreme cold places on this planet and they have multiple adaptations to allow this. They have a multi-layered fur to provide extra insulation and a good supply of body fat. They have blood vessels in their paws that are a countercurrent system; this means there are two sets of blood vessels next to each other with blood running opposite directions, and they also have fur on the soles of their paws to keep them warm and help walk on ice. Because of their size they also have a low surface area to volume ratio (see, the measurements are relevant!) helping to prevent heat loss which means there is less body to cool off and lose heat. All this allows the fox to maintain a good core temperature.

Keeping warm is very important to the arctic fox as it does not hibernate. So unlike a brown bear where they would build up body fat and then sleep in a nice warm cave this fox continues to hunt and survive in the cold arctic winters. They still build up body fat and can gain as much of 50% extra fat to help survive when food is scarce. They have white fur in the winter, and grey-brown or dark brown in the summer to help camouflage and hunt. While hunting they do have a very funny looking trick to help them, since the arctic fox has a keen sense of hearing they can figure out where an animal is under snow and where they are moving toward. When the fox figures out where the prey is they jump into the air and dive head first into the snow in an attempt to catch the prey, it is comical to watch. Jeremy Clarkson (BBC’s Top Gear presenter) has a similar technique to test how deep the snow is.

Since arctic foxes are active all year round they live in large dens in frost free, raised ground. These dens will usually have multiple entrances and can exist for many decades and are used by multiple generations; they often use eskers (long ridges of sedimentary dirt left behind by glaciers). During the mating season they are monogamous and protect their dens. They breed in April and May and gestation lasts about 52 days. They usually have a litter of five super cute pups but can have up to twenty five (largest litter size of any Canivora, which means meat eating animal). Both the mother and father raise them, and they teach them to hunt and scavenge. They have been known to eat lemmings, voles, ringed baby seals pups, fish, seabirds and their eggs, berries and seaweed which makes them omnivores like us humans.
The arctic fox are not endangered but they are hunted for their white fur and some locations are losing their populations of them. They are the only land mammal native to Iceland. You can find the arctic fox in arctic tundra habitats in northern Europe, northern Asia and North America.
To be honest I just wanted to show you the funny video of them jumping into the snow at first but then I discovered its many adaptations for the extreme cold so for these reasons I nominate the arctic fox the EPIC CREATURE OF THE MONTH!

I leave you with some foxes jumping on a trampoline.

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