Martens are carnivores (they eat meat) that mainly hunt at night. They have thin bodies, long, bushy tails, short legs and pointed faces. Their fur is usually brown with pale chest. Martens live in forests and with their claws that are just like cat's they are easily able to climb trees. They live by themselves and do not like other martens living too close to them. They eat mostly small mammals like squirrels, voles, mice, rabbits, but also fish, insects, eggs and sometimes fruits (mostly berries) when available.
They meet to mate in late spring or early summer and have a litter of up to five babies. Little martens, called 'kits', are born blind and naked in early spring, after long gestation.