Humans are dangerous to hippos too! A lot of people that live in Africa or visit Africa will hunt hippos. Just like people hunt deer, turkey, and ducks. This will cause the population (amount) of hippos to lower. Most animals, don't live as long when they are kept in zoos. But hippos actually live a little longer in zoos, because they are away from predators. Hippos typically live about 30-45 years. When they are kept in zoos, they live for about 50 years.