Why are frogs and butterflies important? Endangered species are plants and animals that have become so rare they are in danger of becoming extinct. Threatened species are plants and animals that are likely to become endangered soon. Extinct species are already history. Not a single individual of an extinct species is alive. Butterflies Many species of butterflies are endangered or threatened. Butterflies are very picky eaters. When in their caterpillar stage, most species can eat only a certain kind of leaf. If their habitat is disturbed, they can die out quickly. You can plant a special garden to attract your own state butterfly. Global warming is also hard on butterflies. They are cold-blooded, taking on the same temperature as the surrounding air. If the air gets too warm, many butterflies can't survive. Some of them move to higher and cooler elevations. But butterflies that already live at high elevations are dying out since they cannot move higher. Frogs Frogs and other amphibians are the most endangered groups of animals on Earth. We have lost 170 species in the last 10 years and another 1,900 species are threatened. Frogs are vulnerable to changes in their environment. They have suffered pollution, destruction of their habitat, infectious diseases, and fungus. But all these are made worse by global warming. They are an important part of the web of life, and their health is a good indicator of the health of the environment.