About the ferrets digging a hole through sheets... I've had a sheet stapled to the underside of my mattress for something like 7 or 8 years. What I found was important was to buy one of the more expensive sheets with the higher thread counts. The material is thicker and with the tighter weave ferrets are less likely to get their claws into it. Frequent trimming of the nails helps too. Debra in Fort Worth [Posted in FML issue 3535]