Poop Reveals an Immigrant in Isle Royale Wolves’ Gene Pool

The population of wolves on Isle Royale was formed when a pair of wolves crossed frozen Lake Superior in 1949 from Canada. Since 1958, one of the most important and longest studies of wolf/moose interactions has taken place there. The wolves and moose have fluctuated up and down due to many causes such as tick infestations, genetic inbreeding and fluctuations of forage for moose and prey for wolves. These interactions are seen as a microcosm of wolf prey interactions and demonstrate the many influences on populations.

In the course of this study researchers have found that another male wolf crossed the frozen lake and joined the population. His genes are now represented in 56%, or 9 wolves, of the population of 16 now present on the island.

Besides genetic inbreeding, there is another issue which could eliminate wolves from the island and that is the possible loss of the two remaining female wolves. That has prompted a proposal to bring a few new wolves from the mainland to supplement the population’s genetics and increase their fitness. This runs counter to the National Park Service’s policy to allow natural processes to take place so there will surely be debate about this in the future.

Isleroyalewolf.org has an interesting graph showing the historical wolf and moose population fluctuations that you can see here: http://vicksta.com/wolf%20and%20moose%20graph7.html

Poop Reveals an Immigrant in Isle Royale Wolves’ Gene Pool
Michigan Tech News.

16 Responses to “Poop Reveals an Immigrant in Isle Royale Wolves’ Gene Pool”

  1. jdubya Says:

    The moose/wolf population dynamics are really quite cool, and this is almost a laboratory experiment with only two variables working against each other. It certainly demonstrates to me (but then I don’t need convincing) that trying to match ungulate population fluctuations to a single source of consumption (the wolf) in the western states is a foolish enterprise.

  2. Immer Treue Says:

    I remember speaking with John Vucetich when Isle Royale wolves were still reeling from parvo. There were 12 wolves, three of whom were female. I asked what his impression was in terms of wolf survival on Isle Royale. He replied, “they’re doomed.”

    This was some time ago, now only two females. Much has been made of the genetic bottlenecking on Isle Royale. Comparing it to the wolves in NRM states is like comparing apples and oranges in terms of genetic flow. However, in harmony with Vucetich’s conclusion for IR wolves, if control of moose is important, then something eventually will have to be done.

  3. Mooseboy Says:

    I agree with you 100% on your comment jdubya. Unfortunetly Western Senators don’t seek to find the real truth, they prefer to get their information from lack of proof, uneducated guesses and assumptions.
    Hopefully this spring will bring an increase of moose calfs and wolf cubs in particular female ones. I would love to visit Isle Royale one day and see this amazing labratory for myself.

    • Jeff N. Says:

      Mooseboy –

      Isle Royale is a great backpacking destination. It is where I did my first 3 backpacks back in the mid – 80’s. At that time the wolves were rebounding from a low (at that time) of 14 in the early 80’s wolves but were increasing thru the mid/late 80’s. Saw plenty of moose and some wolf tracks on all 3 trips. I was never fortunate enough to see any wolves but I did hear them howl on 2 of the trips.

      Isle Royale is a heavily forested island full of lakes, swamps, bugs and ridgelines and you can usually expect rain sometime during the week. The island sees very little visitation and it is a true wilderness experience, with some very good pike fishing on a few of the inland lakes, at least back when I visited. I recommend it.

  4. Christopher Harbin Says:

    I would like to think that they have some idea where the wolves would come from to reinvigorate the Isle Royale wolves. It would not be a good idea to wait to the last minute if they do decide to rescue the population.

    • WM Says:

      If I recall correctly Rolf Peterson, in an article within the last two years or so, struggled with whether or how such a genetic rescue could occur. Without it, certainly, the population is doomed. It is even sad that during the time this particular immigrant entered the gene pool he was compelled to mate with his own daughter offspring.

      Query do you continue the experiment to its ultimate end conclusion, or add new genes to keep things going?

      • Jeff N. Says:

        I’m in favor of bringing in a few new wolves. Just not the “Canadian” ones…those sons of bitches are killing machines.

  5. Woody Says:

    Would it be reasonable to bring in one or two pair that have been acclimated to each other from different areas around Lake Superior as Minnesota and eastern Ontario?

  6. Moose Says:

    Given that Lake Superior only freezes over on average once every 15 years now (as opposed to once every 3-5 years previously) I would say the odds of a wolf making its way to the island are next to zero…I would be for letting the experiment run its course…if wolves do disappear it would be interesting to see how the moose dynamics react..At that point perhaps bringing in some mainland MI wolves might be considered….

    • Harley Says:

      Last year it was speculated that one of the wolves, nicknamed Romeo had taken to wandering across the lake but then came back. Speculation of course since he wasn’t collared.
      This is an awesome study, I’ve been following it for about the past 14 years or so and even presented it in one of my biology classes.

    • Immer Treue Says:

      Without wolves, the moose population will climb close to 3,000 as it has once in the past with no wolves, and once with a parvo addled wolf population, followed by a massive die-off.

      • Harley Says:

        Yeah that die off was incredible! Talk about eating themselves out of house and home! I have a friend that goes on the research trips in the spring and he said they followed their nose to the carcasses instead of having to search for the moose bones! I think I would like to see them introduce new blood onto the island. There’s a lot going on with the wolves inbreeding. It would be interesting to see what some new genes would do for the population.

      • Immer Treue Says:


        Winter of 95/96, the wolves didn’t even have to hunt. Dead moose were all over the place. Over about 2 years the moose population dropped from ~2500 to ~500. I believe there was a fir in the 20’s that burned so much moose Winter forage that a similar drop occured, accompanied by similar smells of death.

        Up until ~2000, I used to do an Isle Royale study with my classes. Ubiquitous curriculum changes put an end to that, and I have grown a bit apart from the studies, but the genetic problems the wolves are experiencing is quite telling.

      • Immer Treue Says:

        sorry, should read a fire in the 30’s.

        I’ve got to hit the hay.

      • Moose Says:

        I will look for the doc, but I believe there is little chance moose numbers will return to the 3K levels even if wolves disappear….disease, overbrowsing, and climate change have significantly affected balsam fir stands on the island…


        Isle Royale is definitely a great destination..if you want a cheaper opportunity to hike in amazing UP terrain with as good (if not better) an opportunity to hear wolves…get a US forest service map of Ottawa Nat Forest (head north of Matchwood)

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