In North America the Black-Footed Ferret is the rarest mammal.

The ferret can weigh two or three pounds,and itcan grow up to be two feet long.

The Black-Footed Ferret is yellow or brown,and it also has black feet.

The tip of the ferrets tail is black.

Also it has a black mask around its eyes.

I found this at http://facts4me.com.