Chances are you probably won’t see him again, unless he found his way home.

From faqs.org:

“Domestic pet ferrets, Mustela furo (sometimes called Mustela putorius furo), are not wild animals.

They have been domesticated for a very long time, perhaps two or three thousand years. They’re not equipped to survive for very long on their own; escaped pets suffer from dehydration, starvation and exposure, and usually don’t survive more than a few days unless someone takes them in. Unlike cats and dogs, ferrets aren’t even large enough to push over garbage cans and scavenge.”