Invasive animals pose another major threat to Hawaii’s environment. Some of Hawaii’s invasive animals include: pigs, goats, sheep, rats, mongooses, wild cats, wild dogs, coqui frogs, and chameleons. Each one of these animals has a negative impact on the environment. Rats, cats and dogs all prey on native birds, while frogs and chameleons prey on many native insects.

One of Hawaii’s worst invasive animals is the wild pig. It uproots native plants leaving a wallow where rain collects. Mosquitoes then breed in these wallows. Mosquitoes carry a disease called avian malaria that most of the time is fatal for native birds. A by-product of the pig’s destruction of the rainforest is erosion. When heavy rain falls in the rainforest, which it often does, the areas that have been rooted out by the pigs will flow into the stream and then down into the ocean. The earth that has come down from the mountain acts like a red cloud smothering the reef and preventing sunlight penetration. This kills the reef and many other sea creatures. This damage can be spotted in many areas of the State, including the western side of Kauai and the southern side of Molokai. What happens in the rainforest on the top of mountains will be felt all the way to ocean.