Ecotourism, in which travelers visit natural environments with an eye toward funding conservation efforts or boosting local economies, has become increasingly popular in recent years. In many cases it involves close observation of or interaction with wildlife, such as when tourists swim with marine animals. Now, life scientists have analyzed more than 100 research studies on how ecotourism affects wild animals and concluded that such trips can be harmful to the animals, whose behaviors may be altered in ways that put them at risk.