How do we classify a species as endangered?

Question

Animals which are ovoviviparous, such as some vipers and other snakes, frogs, toads, iguanas and lizards, sharks, and fish, do what?

Answer 1

Endangered animals are animals that are in danger of becoming extinct. This means that there will be no more of these animals alive on earth. An animal is considered endangered or "threatened" when there are very few of them alive.

Some animals are more threatened than others. To keep track of how at risk of becoming extinct a species may be, scientists categorize the level of risk with a different name. From the most threatened animal to least threatened these names are:

1. critically endangered
2. endangered
3. vulnerable