It’s a Mix-up


Some people refer to white-tailed deer as ‘woodland rats’. And there are good reasons for the analogy; whitetails, like Norway rats, can be numerous, they scurry about and they harbor a plethora of diseases and parasites. Still, I like them.

But the disease part is very worrisome. There are two diseases in particular that I have to deal with that can only be described as ‘bad’.

In eastern portions of their range, many deer herds have infection rates of a parasite called the menigeal or brain worm as high as 80%. The worm lives happily in the brain of a deer, but if worms find their way into caribou, moose or elk, it results in sickness and often death. The worm survives by shedding eggs out the deer via feces, which are fed upon by snails and slugs. When these invertebrates crawl up on vegetation, some are inadvertently eaten by deer, returning a new generation of brain worms to the host. When there are lots of deer and snails, it’s highly likely almost every individual cervid will eventually eat an infected snail. It doesn’t do the whitetail deer any harm, but the other species aren’t so lucky.

I’ve never heard of a human with brain worm, and I don’t know if it’s even possible to get infected.

Chronic Wasting Disease (CWD) is another disease that’s worrisome. This one, though, is somewhat less discriminatory as to who survives: no one, at least as far as is known to date. Any whitetail or mule deer, moose or elk that gets infected, dies. Caribou with the disease have yet to be found, but likely only because they have not as yet come into contact with it. Humans don’t get CWD, at least not so far as is known.

The problem with whitetails and this disease is mainly the fact whitetails are so numerous and widespread. They’re everywhere, mixing with mulies, moose and elk (actually, they aren’t everywhere. But they do have a large range of distribution, much greater than mule deer, moose or elk). Only caribou in the far north have greater range occupancy than whitetails. There is little to no range overlap with deer and caribou – when this has occurred, caribou lost out quickly and completely.

This winter will reduce whitetail populations considerably across a huge swath of North America. For moose, elk and maybe even mule deer and caribou, that’s probably a good thing.

But like rats, many whitetails will survive. They survive severe winters by finding people willing to feed them, or finding some hidey-hole safe from predators where they’ll just sit tight and try to wait it out. Or something.

The white-tailed deer is a survivor. Just like the Norway rat.

  1. randy mccune said:

    Bruce, Enjoying your blog. Sorry to connect it too this entry. Last week I had a photo job and on this guys wall was a photograph of a caribou. This guy is a great lakes power boater and has been on the island off Wawa and has seen the caribou on this island. I would be interested in a story regarding the history of the island. Maybe it would be better as a magazine article. Been to Isle Royale and have followed the wolf/ moose interaction, but would be most interested in this island. I remember years ago you talked about the island when you worked in SSM. Just a thought. Funny thing, out back a patch of dirt showed up on the edge of the swamp. Is that really a sign of spring? Randy

  2. The island in Lake Superior offshore of Wawa where there is caribou is called Michipicoten. Caribou were introduced to it in the last couple of decades, are apparently doing well and their numbers are increasing. There were also caribou on the mainland (native) just to the north, in Pukaskwa National Park up until recently. Park staff believe the last caribou finally disappeared from there a couple of years ago.
    There are also caribou on the Slate Islands near the towns of Terrace Bay and Marathon. These islands are a Provincial Park. The caribou on the slates can be very numerous (well over a thousand), but populations fluctuate wildly. For the most part, there are no timber wolves on the Slates, although a couple did show up a few years back. They didn’t stay all that long, and didn’t produce any offspring. Some winters the caribou on the Slates rely on lichens being blown out of the tops of trees for their survival.
    We’re getting another snow storm today, with high winds and dropping temperatures. No more above freezing temperatures until this Friday – as if it’s been warm! I heard from a friend of mine there was about 42″ of ice when he was out fishing recently (about the same on three different lakes). He never had a bite.

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