paw pads remaining visible even in winter. Because of its shorter limbs, the beech marten's manner of locomotion differs from that of the pine marten; the beech marten moves by creeping in a polecat-like manner, whereas the pine marten and sable move by bounds. The load per 1 cm2 of the supporting surface of the beech marten's foot (30.9 g) is double that of the pine marten (15.2 g), thus it is obliged to avoid snowy regions. Its skull is similar to that of the pine marten, but differs in its shorter facial region, more convex profile, its larger carnassials and smaller molars. The beech marten's penis is larger than the pine marten's, with the bacula of young beech martens often outsizing those of old pine martens. Males measure 430–590 mm in body length, while females measure 380–470 mm. The tail measures 250–320 mm in males and 230–275 mm in females. Males weigh 1.7–1.8 kg in winter and 2–2.1 kg in summer, while females weigh 1.1–1.3 kg in winter and 1.4–1.5 kg in summer. The beech marten's fur is coarser than the pine marten's, with elastic guard hairs and less dense underfur. Its summer coat is short, sparse and coarse, and the tail is sparsely furred. The colour tone is lighter than the pine marten's. Unlike the pine marten, its underfur is whitish, rather than greyish. The tail is dark-brown, while the back is darker than that of the pine marten. The throat patch of the beech marten is always white. The patch is large and generally has two projections extending backwards to the base of the forelegs and upward on the legs. The dark colour of the belly juts out between the forelegs as a line into the white colour of the chest and sometimes into the neck. In the pine marten, by contrast, the white colour between the forelegs juts backwards as a protrusion into the belly colour. Behaviour and ecology The beech marten is mainly a crepuscular and nocturnal animal, though to a much lesser extent than the European polecat. It is especially active during moonlit nights. Being a more terrestrial animal than the pine marten, the beech marten is less arboreal in its habits, though it can be a skilled climber in heavily forested areas. It is a skilled swimmer, and may occasionally be active during daytime hours, particularly in the summer, when nights are short.