MNN Galleries

10 animals that are bad for the environment

Rat on a woman's shoulder

Photo: ArtBrom/Flickr

10 of 12

Rats

Rats are wildly successful animals wherever they live — a characteristic that make them dangerous when they are introduced to non-native areas. One primary example has been the introduction of black rats onto Lord Howe Island, a small habitat in the Tasman Sea, where much of the island's unique native wildlife has been wiped out by invading rats. Rats can also be the bearers of disease, and rat population outbreaks can cause substantial food losses, especially in developing countries.