In the wild, pine martens may mate in their first summer at 14 months of age, but in captivity most males don’t breed until 27 months old.

In the wild, male and female pine martens may mate in their first summer, at 14 months of age. The first mating season, however, may typically be deferred until the second or third year.

In captivity, most males do not breed until 27 months old. This could be due to stress incurred under captive conditions or inaccuracy in aging wild animals.

Sources: (Mead, 1994; Schwanz, 2000)
Image: Phil Fiddes