What are the causes of extinction?
If you've read about the different animals on these pages, you'll see that they have become endangered or extinct for many different reasons. Conservation biologists - scientists who try to stop endangered species from dying out - use the word 'hippo' to remember the different things that threaten animals and plants, because each letter of 'hippo' stands for a different threat.
Click on each of the letters on the hippo below to find out what each one stands for.
Find out about the extinct and endangered animals in the Museum.
Go to the Homepage to find out about hippos and the causes of extinction.