Long-tailed weasel, short -tailed weasel, Least Weasel, mink, otter, fisher, martin are just a few of the members of the weasel family found in North America. The family name, Mustelidae, is based on the Latin word for "weasel". Anyone who has had the pleasure of raising one of these animals will quickly tell you that they are the coolest animals to raise.
Weasels are usually born in April or May in underground dens, and it is pretty much a given that any infant of a burrowing or tunneling species found above ground is in trouble and should be taken to a rehabilitator. The long , skinny neck is usually a give-away to the fact that one has a weasel, but it can often be difficult to determine what species one has until at least a couple weeks old. But, determining the species of weasel really doesn't matter when it comes to the care needed, as they are all cared for the same.
Baby weasels are interesting in many ways, and the fact that I find most interesting is that their eyes don't open for 26 days. I am used to fox pups whose eyes are open by two weeks of age. When their eyes open, they are eating soft solid food. However, weasels are eating solid food WELL BEFORE their eyes open. One of my pet peeves are rehabilitators who bottle feed animals well past the time that they should. I observed a scrapbook recently that a rehabilitator was using for public display. While flipping through the pages, I saw a nearly adult-sized fully furred, eyes open "baby" weasel" drinking formula from a bottle. EEK! I thought. Surely one must have a better feel for mammals than that? Eyes still closed and baby fur still on, offer some canned cat food and watch the baby chow down. I always mix the formula with a product called 'Missing Link for Cats" It comes in a gold foil pouch and is sold through catalogs and outlets, including PetSmart. Weasels need a basic diet like a cat, not a dog. I strongly believe that a balanced diet is more easily obtained by feeding a canned and dry cat food that has been manufactures to provide cats with a balanced diet. The Missing Link should be added to all foods, including the formula. Feeding just mice is not a balanced diet, as wildlife eats such a variety of things that a single source of food simply doesn't provide . Small, dead mice should certainly be offered to young baby weasels (and young fox pups), but only as an enrichment, a prey-identification tool, not as a diet. When raised in captivity, animals simply do not have access to the dirt, insects, minerals, and grasses that they do in the wild. A diet of dead or live mice and chicks is simply inadequate.
Since weasels have such an incredibly fast metabolism, it is advisable to feed them every hour, right around the clock until they are at least 2 weeks old. I feed a mix of formula, canned cat food, Missing Link for Cats and Pedialyte to help with hydration. I thicken the formula as they show preference for chunks of solid food. When they are three weeks old, I feed them every three hours. I will also give small chunks of chicken or venison.
Even before their eyes are open, I am sure to have them in natural surroundings, with leaves, clumps of grasses, rocks and logs. Of course there is an area that provides warmth and snuggle space. By five weeks old, baby weasels are weaned in the wild - but I find that they are off the milk formula before that in my care, and on to canned cat food, dry cat food, meat, mice.
Here is an interesting fact... Females can conceived while they are still in the nest and their eyes and ears are still cosed. By the time they leave their nest, many females are already pregnant. Weasels generally mate in July or August, but the young are not born until the following April or May. The total gestation is roughly 279 days. The young are not actually developing during this period though. The embryos undergo an initial development of about two weeks, then remain free in the uterus,.dormant until April or May when they are implanted 23 to 24 days before birth. There are usually 5-8 blind, toothless, pink and naked young.
The most common predators of weasels are man, cats, dogs, owls, foxes, hawks and snakes. Weasels are very susceptible to distemper and it is advisable to vaccinate them with a safe vaccine, such as PUREVAX, a canary vector vaccine made by Merial. Any other distemper vaccines give to animals especially prone to distemper can actually cause them to come down with the disease. PUREVAX is a new vaccine that has proved safe in wild animals.