A Gray Titi Monkey was born at the Bronx Zoo in April and has just now gone made it's debut on exhibit with mom. In fact, you can hear them sing together early in the morning.
Gestation for the Bolivian gray titi monkey is about 132 days, a little over 4 months. A single baby is usually born; very rarely, twins are born. Gray titi monkeys live in family groups, which usually consists of a breeding couple and several offspring. The father will help wtih the baby, carrying it on it's back in the first few days after birth. Older brothers or sisters may also help in this same way.
The Wildlife Conservation Society, which owns the zoo, works in Bolivia where gray titi monkeys live in the wild. This species is endangered largely due to habitat destruction.