Habitats.

Part fourteen mammals of the mountain sides.

Britain`s mountains are not very high-only one, Ben Nevis is, above 4,000 ft (1,200m)- but they are bleak places for warm blooded creatures to live, especially in winter. For roughly every 500ft (150m) of height above sea level, it gets almost two degrees colder. Rain and mist as well as stronger winds also add to the chill. Trees rarely grow on high, windswept uplands, so there is little shelter. Consequently, few mammals live on the exposed high ground. Although they forage on the heights in summer, red deer and, to a lesser degree, mountain hares move to lower ground for the winter. Small mammals, such as field voles that live amid the upland grass, do not make long migrations. Although they lose a lot of body heat because they have a large surface area of skin in relation to their bulk, they can find shelter in burrows or among thickets of heather or bilberry. Despite the cold, small spiders and insects are surprisingly numerous amid upland vegetation, and provide food for pygmy shrews. Stoats thrive on field voles but will also take meadow pipits and other upland birds. Crows and foxes search the mountain- sides for carrion such as dead hares and sheep. Small herds of feral goats may be seen in a few mountainous areas. They vary widely in colour, ranging from white to piebald, skewbald, dark brown or black. Young goats are not likely to be seen before April. In their winter pelage, mountain hares look like snow against the dark heather. They show up only when they move. On upland slopes they take the place of rabbits and brown hares. Many upland areas now have commercial plantations of dense conifers(some wildlife trusts are now taking some of these out). They rob mountain hares of their living space, but may provide homes for pine martins. Red deer move down the valley during winter, returning in spring. Stoats have great camouflage in winter because of their winter pelage. It also helps to preserve body heat, because white fur radiates less than dark fur. Where there are meadow pipits there may also be pygmy shrews. Both feed on tiny insects among the stones and heather. Pygmy shrews remain well hidden but nay be heard squeaking.

photo periodic pelage reaction

In the u.k there are four animals that turn white in winter,ptarmigan,mountain hare,stoat and the weasel. They do this to avoid predation from golden eagles in the cairngorms. Photo periodism- The eye records the local day lengths and this is the photo-periodism, they then communicate this information to the brain, which then relays it to their hormonal or the endocrym system. This then produce`s a compound called melatonin. This compound inhibits the production of pigments so when they moult the new feathers and fur come through white. The speed of change is not controlled by the day length but by the air temperature. They will go whiter quicker at higher altitudes. Because of genetic factors, Southern weasels and stoats couldn't`t go white anymore. There are microscopic sub structures of bubbles in the ptarmigans feathers to keep them warmer. Mountain hare`s coats are thicker in winter and when a stoat moults it goes whiter from the feet and belly first, This is because they are closer to the ground and it keeps the stoat warmer.The reverse happens in winter with the stoats nose going white first followed by the rest of its body down to its feet.