Cheetahs only seem to be ferocious and very dangerous predators (though it’s not a good idea to pull their whiskers!), and they are actually very shy. When they get anxious, they cannot breed, so they become extinct.
To help them overcome it, zoo keepers use dogs to make friends with cheetahs and make it easier for them to learn how to behave. Cheetahs look at the dominating dog, mimic their confidence and attitude and eventually get ready to have their own family.