These mink eat voles, crustaceans, insects, birds, frogs, and vegetation. They are about 12-15 inches long. Unfortunately they have had a population decline of over 50% recently, and is expected to decline significantly still. Interestingly, the American mink is one of the reasons that reintroductions have not been going well. The American ones are direct competitors, a little bigger (up to almost 30 inches long), better at adapting to diminishing habitat, and are don't tolerate other predators. They escaped from fur breeders and thrived, and will defend their territory from any European ones released near them. Captive breeding of the European Mink works, but if they don't raise them along the river, the European Mink gets confused when released and has no idea where they should live. They are more closely related to the Siberia Weasel than the American mink in spite of the similar look and name.
I've thought about having a pet ferret. Unfortunately, we have a terrier-whatsit mix. Terriers are born killers when it comes to fuzzy little things. We were on a walk with by the waterfalls him many years ago when he suddenly just dove off the pathway. Before we knew what he was doing, he'd grabbed a vole we hadn't seen, given it one shake, and dropped it feeling quite proud of himself. He is blind now, but he still chases squirrels if they make a noise in our yard. I don't think a ferret would be safe even if he can't see it, he could smell it and would certainly try to end its life. You can't fault him, he's just doing what his genetics tell him to do. He's the most timid dog I've ever known. He is terrified of beeps. He used to love car rides, until a woman t-boned us after she ran a stop. Now he's terrified of car rides. He gets his temperature taken in his armpit at the vet's. He goes into statue mode at the vet and they literally cannot manipulate his limbs, they've tried! He loves thunder, loves vacuum cleaners, and loves fireworks, but if some nice stranger tries to pet him he will scream this awful almost human scream.