<http://schema.org/alternativeHeadline>
"European zoos often put down healthy animals to maintain genetic diversity in a species' population, but the practice doesn't occur in U.S. zoos. Why? It all comes down to birth control."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mnn.com/earth-matters/animals/stories/why-do-some-zoos-euthanize-healthy-animals>