• The beech marten gives birth to three or four young, which are blind and naked at first. Eight months pass between mating and birth, and the gestation period lasts only one month.

The European pine marten, also known as a beech marten or house marten, has a typical lifespan ranging from 13 years and 8 months to 22 years and 9 months, with a maximum lifespan of 18 years and 3 months, while its theoretical lifespan is between 9 years and 1 month and 16 years and 5 months; the species reaches sexual maturity at an age of 1 to 2 years. During the "Embryo" stage, the fetus develops inside the mother, and pregnancy lasts for a prolonged period. The "Young" stage begins when the young’s eyes open between 3 weeks and 1 month and 1 week; the young are born blind and hairless, and the mother feeds them milk in a den for a duration of 1 day to 1 month and 3 weeks. The "Adult" stage commences at an age of 1 to 11 years, during which the species hunts independently and lives separately, with males being larger than females.