STEVE INSKEEP, HOST:

Good morning. I'm Steve Inskeep. Species of life spread different ways. Seeds are carried by birds, for example. But this is not what happened with the hippos of South America. Colombian drug lord Pablo Escobar brought four hippos years ago for his private zoo. They've now multiplied to around 80. Colombia is so congenial to hippos that authorities worry about their environmental impact, so they plan to shoot them with contraceptive darts.

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