How developed is a newborn gorilla?

After a pregnancy that lasts on average 257 days (humans: 265 days), gorillas usually give birth in less than half an hour and the mother does not seem to feel great pain. However, difficult births do occur and can take up to three days. Twin births occur approximately as often as in humans, but free-ranging mothers usually do not raise both twins. Newborn western gorillas weigh between 1,396 and 3,058 g (2,200 g on average), compared to 3,300 g in humans. This means that while adult females and males weigh approximately twice and three times as much as average humans, their newborn babies are only two thirds the weight of newborn humans.

Newborn gorillas are quite helpless: they cannot coordinate their movements and see very little, just as human babies. The facial skin is relatively pale, whereas palms and soles usually show irregular, pale patterns on a dark skin. In many places the body hair is very sparse; the longest and densest hair is on the head.

Young gorillas show the same reflexes as newborn human babies. Among them are the instinctive searching for the nipple and the clinging reflex. The latter is much better developed in gorillas because the babies have to be able to cling to the mother's body without help.