MARSHALL BRAIN, HowStuffWorks.com | Posted: Monday, February 4, 2008 12:00 am
Many of the Earth's animals - especially some of the biggest and most interesting ones like elephants - are at risk for extinction. Twenty-five years ago, there were 2 million African elephants in the wild. Today there are fewer than 600,000. The Asian elephant is even more at risk. It numbers only 40,000 in the wild.
Zoos are trying to preserve animals by helping them breed in captivity. Most zoos and aquariums in the U.S. belong to the Association of Zoos and Aquariums. The AZA has created a species survival plan, under which more than 150 species are actively breeding in zoos. They are genetically diverse populations, so that even if the animals went extinct in the wild, zoos could maintain viable populations in captivity.
Some animals breed so well in captivity that they actually have to be slowed down. For example, at the North Carolina zoo, all of the zebras and all of the ostriches are female to keep them from reproducing.
Other animals have been difficult to breed in captivity. The zoos work with the animals that are having problems and try to find better ways to help them breed.
There have been some real successes for the zoos. For example, red wolves had nearly gone extinct. There were only 14 unrelated red wolves on the planet. Zoos were able to breed wolves in captivity, back up to a population of 200. Then they released some of the wolves into the wild in North Carolina forests. Whooping cranes worked the same way. They were nearly extinct, and zoos brought them back to life.
Zoos also work hard at field conservation programs. They try to keep habitats from disappearing. They help people in Africa and other countries set up preserves and parks where the animals can live. It is a huge job, and zoos are taking the lead.
Keeping some of these species alive is not easy. Take elephants, for example. Elephants are especially hard to breed because they need a lot of space and they like to live in large groups. The North Carolina zoo is investing in a 50-acre exhibit called that Watani Grasslands Reserve. The elephants will get 7 acres all to themselves in the exhibit. Eventually there will be a herd of 10 elephants. So the zoo is acquiring four new animals.
At the North Carolina zoo, the goal is a herd of 10 elephants. There will be three females the zoo will try to breed. Once born, the baby elephants will become part of the species survival plan.
Animals suitable for breeding - not too old or too young and not too closely related - are loaned between zoos as part of one giant herd.