Scottish mountains comprise the largest upland area in Britain, with over 90% of the British total above 610m (2,000ft) and 98% above 915m (3,000ft). They include the highest mountains in the British Isles. Geologically, Scottish mountains are full of interest, containing some of the most ancient outcrops known. The natural history is also celebrated, from the occurence of specialised montane plants, mammals and birds to economically important grouse and deer. Less well known, however, are the insects.