Pine martens are born blind, deaf, and toothless with thick, short fur and don’t begin emerging from the den until 7-8 weeks later.
At birth, young pine martens weigh about 30 grams. They are blind, deaf, and toothless, and have thick, short fur. In the nest, young pine marten communicate to their mother by twittering.
The eyes open at 34-38 days. Young martens begin consuming solid food at 36-45 days, and weaning occurs about six weeks after parturition. At 7-8 weeks, the young emerge from the den and may begin dispersing at 12-16 weeks, during the breeding season. Some young may overwinter in the natal territory and disperse in the following spring.
Juvenile pine martens acquire their adult pelage in their first winter.