Minichan

Zookeepers around the world, facing limited capacity and pressure to maintain diverse and vibrant collections of endangered species, are often choosing between two controversial methods: birth control and euthanasia.

In the United States, the choice is contraception. Chimps take human birth control pills, giraffes are served hormones in their feed, and grizzly bears have slow-releasing hormones implanted in their forelegs. Even small rodents are included.[...]

But in Europe, some zookeepers would rather euthanize unneeded offspring after they mature than deny the animal parents the experience of procreating and nurturing their young.

“We’d rather they have as natural behavior as possible,” said Bengt Holst, director of conservation for the Copenhagen Zoo. “We have already taken away their predatory and antipredatory behaviors. If we take away their parenting behavior, they have not much left.”

So he and many of his European counterparts generally allow animals to raise their young until an age at which they would naturally separate from parents. It is then that zoo officials euthanize offspring that do not figure in breeding plans.

This spring, the Copenhagen Zoo put down, by lethal injection, two leopard cubs, about 2 years old, whose genes were already overrepresented in the collective zoo population.