Wild horses roam parts of Vieques, and although they look gentle and placid while grazing on the tropical underbrush, they can kick, bite and trample. Even small animals are capable of inflicting serious injury or even fatal wounds on unsuspecting tourists. Some also carry rabies. Keep your distance from all wild animals, and that goes double for any mongooses you see in El Yunque. The monkeys and iguanas on some of the cays off the south coast can be downright fierce.