Mine have discovered how to
1- Open their cages.
2- Untie the knots holding their hammocks to their cage using their front paws and nails.
3- Unzip the zippers on my pocketbooks to see if there's anything interesting inside.
4- Move objects across the room so they can climb on them to reach something they're not supposed to have.
And they can also do just about anything you can teach a dog to do. Here are a few of the tricks that I've had the pleasure of teaching my ferrets.