Pelage brown in summer, white in winter. Long black-tipped ears. Weight: approx 2500-3500 g - females slightly heavier than males.
Mountain hares are also known as blue hares, or colloquially in winter, as white hares. It is considered to be the same species as the Arctic and Greenland hares. They are indigenous to Britain, unlike the other lagomorphs, the rabbit and the Brown hare, which were probably introduced by man. Although elsewhere in its broad circumpolar distribution, the mountain hare mainly occupies Boreal forest, in Britain it is associated with heather moorlands, particularly those which are managed by burning in strips for red grouse.
Population densities of mountain hares fluctuate periodically, varying at least 10-fold, and reaching a peak approximately every 10 years. On grouse moors in the north-east of Scotland, peak population densities of up to 250/km2 have been recorded, but hares are only patchily distributed and at low densities on moorlands to the west, north or south of Scotland. There are introduced populations in the Peak District in northern England, and on some Scottish Islands including Orkney, Shetland, Mull and Skye.
Mountain hares rest during the day in forms and scrapes which provide shelter and they sometimes make burrows in the earth or in snow, particularly when young. Their runs usually pass directly up slopes, rather than traversing slopes like those of sheep and deer. They are active at night, and although considered to be browsers of woody plants such as heather and other dwarf shrubs and trees, they prefer to eat grasses when they are available during the summer months. During periods of snow cover they gather on leeward hill slopes, in groups of 20+, to shelter or feed where shallow snow permits scraping to reveal underlying heather. They are preyed upon by several predators including foxes, stoats, cats and raptors.
Male mountain hares are sexually mature each year before females, and mating takes place from the end of January onwards; gestation is 50 days. The season of births of leverets varies between years but is mainly in the months of March-July. Neither females nor males, are known to breed in their year of birth. Females show a range of reproductive strategies producing between one and four litters, of 1-3 offspring, but occasionally more. Larger females breed earlier, and females in their first year suffer higher prenatal mortality in their earliest litter. Their reproductive behaviour is similar to that of Brown hares, with several males chasing a single female who may rebuff them by boxing. The newly born leverets are fully-furred, have open-eyes and receive little parental care other than suckling visits by their mother.
No systematically collected information is available on long-term changes in numbers of mountain hares, over and above the usual periodic 10-year fluctuations, although on some western Scottish moors they are now rare where they were previously abundant. Their numbers have declined locally where favourable habitat such as former grouse moors has been afforested or heather has been removed by excessive grazing by other animals. Young forestry plantations can support high densities of hares which sometimes cause significant damage to trees, but these high densities decline once the forest canopy closes, and the ground vegetation is diminished.
Mountain hares are listed in Annex V of the EC habitats directive (1992), as a species 'of community interest whose taking in the wild and exploitation may be subject to management measures'. This conservation status means that certain methods of capture are prohibited or restricted. Mountain hares have historically been considered as small game with little commercial value either as a meat source or for shooting revenue. However, the shooting which usually takes place in the winter months is becoming increasingly commercialised, due to shortage of other game.
Why do mountain hares turn white in winter?
This characteristic may have evolved originally to provide camouflage from predators in winter. It has also been suggested that the white coat colour of mammals in high latitudes provides a thermal advantage; the scattering of light in the lower layers of fur results in a type of 'greenhouse effect' causing a warm layer near to animal's skin. The mountain hares in Ireland (Lepus timidus hibernicus) do not turn fully white in winter.
Do mountain hares compete with Brown hares?
In Britain the mountain hare occupies higher latitudes than the Brown hare. This reduces current competition between them but may be the result of previous competitive exclusion. The mountain hare is physiologically better suited to eating poorer quality food such as woody browse in winter, and its thick winter coat makes it tolerant of cold climatic conditions. In Ireland where the Brown hare has only been introduced to some areas, the mountain hare occurs down to sea level and feeds on grasses wherever they are available.
Corbet, G and Harris S (1991) The handbook of British Mammals. 3rd edition. Blackwell, Oxford.
Flux, J.E.C. (1970) Life history of the Mountain hare (Lepus timidus scoticus) in north-east Scotland. J. Zoology, London, 161, 75-123.