The largest of the living apes, the gorilla has a characteristically heavy body shape and shaggy dark coat. Until recently it was considered a single species, but DNA evidence has led to the recognition of the eastern and western populations as distinct species; Gorilla beringei
and Gorilla gorilla
respectively (4). Gorillas have robust bodies with broad chests and long arms. The mountain gorilla subspecies (Gorilla beringei beringei
) has a particularly long coat, which is blue-black to brownish-grey in colour. Mature male gorillas are much larger than females with a large skull crest. At about 14 years old, the hair in the saddle of their back turns white and hence they are known as 'silverbacks' (2). Gorillas are quadrupedal, walking on the knuckles of their forelimbs and the soles of their feet (2).