The word ferret has its origin in Latin and is translated as pilferer. With that bit of knowledge, it should come as no surprise that ferrets like to steal things and hoard them.
My ferrets take everything they can drag. I have seen my little girl, weighing a pound, try to remove the sterilized bone from the dog; the bone weighs more than her. (The only reason she was unsuccessful is that the dog saw her dragging the bone across the room and intervened.) They have appropriated my shoes, my wristband and my stuffed animals. They have snatched markers, balls and plates of food. They have stolen computer mice, tissues and socks. They have removed apples, potatoes and staple removers. If they can hack an article, they will.
So after my ferrets acquire an object of desire, they treasure it. Almost all things stolen end up in the same place. After cleaning, they may relocate your stash, but there is usually only one cache at a time. I found the hiding place under his cage. One time the hiding place was behind the television and one time they put it all inside one of my husband’s speakers. Currently, my babies like to relocate objects inside their Tower of Fun, a tube that rotates up and down. The furry ones like to slide down the slopes of the Tower of Fun, so it’s a bit strange that they block their fun gliding route with toys. Yet they do.
As I do not speak ferret, and my ferrets do not speak human, I can only guess based on their natural behaviors in the wild. Polecats (from whom our domestic ferrets have been domesticated) are carnivores. They are hunters. They kill things smaller than themselves (usually smaller, but I’ve seen videos of ferrets killing things bigger than themselves). So a ferret kills a mouse and eats it. When it’s ready, it will hide the leftovers. If a ferret kills an animal that is too big to eat in one sitting, the ferret will hide the carcass to finish it later. And, in all these cases, ferrets try to prevent other animals from obtaining their loot.
I think that’s probably the best explanation for why ferrets steal, but I have another thought. I frequently find sleeping ferrets among their stolen treasures. Usually when they sleep in their stash, the items are soft and squishy, like little stuffed toys and other fluffy things. So my second hypothesis is that ferrets like to build comfortable beds.