Our planet is rich in life. Tigers and turtles, bats and bees, gnats and gnus, crabs and crabgrass -the list seems endless. We have named more than 1.5 million species, and suspect that millions more remain undiscovered. Scientists call this mind-boggling variety of life biodiversity. With so many species, it is surprising to realise that so many are in danger of becoming extinct.
Extinct species are plants and animals that once lived on Earth, but no longer live anywhere in the world. Endangered species are those most in danger of extinction. Even large populations of animals can be at risk. Passenger pigeons once darkened the skies of the US. Over time, habitat destruction and hunting decreased the population of these birds. The last one died alone at the Cincinnati Zoo in 1914.
Dinosaurs, dodos and passenger pigeons are all extinct. Extinction used to happen naturally, but in modern times, people have pushed wildlife to the brink much more quickly than ever before. We are losing wildlife very rapidly!
After realising this severe situation, many countries and international organisations have carried out rules and principles to protect endangered animals. The US Endangered Species Act of 1973, for example, was passed to protect threatened wildlife and habitats so they don't go the way of the dodo.
So why do animals become endangered? The main reason is the loss of habitats. Habitat destruction can make it extremely hard for wildlife to survive. However, as people learn to take better care of plants and animals as well as their habitats, endangered and threatened species may begin to make a comeback. In fact, many species such as bald eagles already have.
