Young gorillas learn by mimicking the behaviors of other individuals in the troop, and by play fighting with other youngsters. A young gorilla stays close to its mother until it is 4 to 6 years old. Gorillas are known to nurse for up to 3 years.
Monroe, a gorilla, is such a mama's boy. Here, he is seen clinging onto his mother at the San Diego Zoo. Even though Monroe might seem a bit old to be so attached to his mother, gorillas have been known to nurse for up to three years.