A characteristic feature of narwhal is a spirally twisted horn.
It grows from the left side of the upper jaw. It can reach 3 meters in length and weigh up to ten kilograms. Female fangs are slightly shorter and smoother than male fangs.
The body length of a european marten averages 53 cm (21 in) and the tail length is 25 cm (10 in). Adult martens can weigh between 1.5 and 1.7 kg (3,3 to 3,7 in).