European pine martens typically live from 18 to 30 years, with a maximum recorded lifespan of 18 years and 3 months, and a theoretical lifespan ranging from 7 years and 2 months to 29 years and 9 months. The species reaches sexual maturity from 11 months and 2 weeks to 1 year and 7 months. A pine marten's young have their eyes open from 3 weeks to 1 month and 1 week; during the embryonic stage, the embryo develops inside the mother’s body, with the entire gestation period lasting up to nine months due to delayed implantation. The newborn is blind and hairless, remaining sheltered while drinking its mother’s milk and growing rapidly during a period of from 1 month and 2 weeks to 3 months. Subsequently, the species enters the adult stage, lasting from 1 to 10 years, during which time it hunts independently, climbs trees, and defends its territory.