What makes an animal endangered?

Question

For example, when the population dips below a certain number, and what is that number

Answer 1

There is no "x" set number for species to be considered endangered because there are various factors to consider for each animal.

For example....
-How large of a range is left for the animal to live in.
-How often they breed.
-Number of young they have.

On top of that there are other factors such as new diseases/illnesses that develop in the species.

Like I said there is no set number due to the fact that each species is different and circumstances are always changing.

Answer 2

http://en.wikipedia.org/wiki/Endangered

Jim, http://www.jimpettis.com/wheel/