Beware the ecotourist.

The massive growth of the ecotourist industry has biologists worried. Evidence is growing that many animals do not react well to tourists in their backyard. The immediate effects can be subtle changes to an animals' heart rate, physiology, stress hormone levels and social behaviour but in the long term the impact tourists are having could endanger the survival of the very wildlife they want to see. Poor countries that are rich in biological diversity benefit from the money tourists bring in, supposedly without damaging the environment. INSET: WITH VISITORS COME DISEASES.