A female Japanese macaque nursing her few weeks old infant. Japanese macaques give birth to their infants between spring and early summer and nurse it for seven months to a year. After about a month, the infants begin to eat additional solid food. By winter, they are strong enough to survive the cold months.

A female Japanese macaque nursing her six-month-old infant in winter. Japanese macaques, also known as snow monkeys, give birth to their infants between spring and early summer so that they are strong enough to survive the cold winter months.