Siberian tigers reach sexual maturity at four years of age. They mate at any time of the year. A female signals her receptiveness by leaving urine deposits and scratch marks on trees. She will spend a week with the male, during which she is receptive for three days. Gestation lasts from three to 3½ months. Litter size is normally three or four cubs but there can be as many as six. The cubs are born blind in a sheltered den and are left alone when the female leaves to hunt for food.
Cubs are divided equally between genders at birth. However, by adulthood there are usually two to four females for every male. The female cubs remain with their mothers longer, and later they establish territories close to their original ranges. Males, on the other hand, travel unaccompanied and range farther earlier in their lives, thus making them more vulnerable to poachers and other tigers.