Do Wolves Experience Mid-Life Crisis?

October 29, 2009 at 4:11 pm 5 comments

No, that kind of pointless angst is reserved for intellectually over-indulgent species like humans.  But, contrary to common myth, wild wolves don’t necessarily live hard and die young either. Doug Smith, Yellowstone Wolf Project leader at the Yellowstone Center for Resources was recently quoted in Minnesota Daily;  “Through mythology and fables, we want wolves to be a certain way and that is supremely good at killing,” he said. “It turns out they’re subject to the same problems we’re subject to. You get old quick.”

 Science Daily reports:

Although most wolves in Yellowstone National Park live to be nearly six years old, their ability to kill prey peaks when they are two to three, according to a study led by Dan MacNulty and recently published online by Ecology Letters.

As is the case with human beings, physiology appears to be an important factor.  Wolves need to have speed, strength and endurance to hunt successfully – and these qualities diminish with age.  This leads to some interesting economic parallels between our world and the world of the wolf:

When older wolves can no longer hunt successfully, younger wolves share their kill with them, in what MacNulty describes as a lupine version of Social Security. While a high ratio of old-to-young wolves may benefit elk, it could strain the wolf population because there aren’t enough workers to support retirees.

Montana legalized hunting wolves after they were removed from the endangered species list in 2007. Although hunting is prohibited in the park, packs wander beyond it boundaries and radio-marked wolves have been killed. MacNulty says hunting won’t put the species at risk, but it actually skews the population towards younger wolves, which could mean more deaths, not fewer, for the elk.

As quoted in BBC News MacNulty notes that aging in wild animals has (surprisingly) been a controversial subject:

“Although the effects of aging on physical performance in humans are well-known, the effects of aging in wild animal populations have been controversial,” says Dr Daniel MacNulty of the Michigan Technological University in Houghton, US.

“Many eminent biologists have argued that ageing rarely occurs in nature, because animals do not live long enough to exhibit its effects.”

“My study refutes this notion as well as demonstrates that aging may have important ecological consequences in terms of how a wild population uses its environment,” he says.

Wolves are brilliant cooperative hunters. Younger pack members supply speed and endurance to the chase - and older ones the wisdom they’ve acquired over years of experience.  I look forward to seeing more on how hunting affects the balance of old versus young members of wolf packs and how that, in turn, affects populations of their prey species.  If young wolves help feed older ones, and if wolves only kill what they need to eat, I’m not clear on exactly how a higher percentage of young pack members acts to decrease elk populations.  Intuitively it would just seem to mean that the young wolves don’t have to work as hard to feed themselves, and if hunting pressure continues to keep wolf numbers stable it isn’t obvious (at least to me) that elk numbers would be greatly affected. 

I’d also like to know more  about what kinds of wolves hunters look for. Tropy elk are pretty easy to identify from a distance, but it can’t be easy to get close enough to a wolf to tell its gender or, in many cases, its age.  Do hunters typically look for the biggest wolf, the one with the nicest pelt - or the easiest one to take down?   And how do ranchers who want to limit predation fit into the equation? 

It seems that today I’ve got more questions than answers.

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Entry filed under: science, wildlife. Tags: , .

In Other News End of the Rainbow

5 Comments Add your own

  • 1. H. Houlahan  |  October 29, 2009 at 7:36 pm

    If young wolves help feed older ones, and if wolves only kill what they need to eat, I’m not clear on exactly how a higher percentage of young pack members acts to decrease elk populations.

    Not included in the article, but with coyotes, it was established that human-caused mortality drove much higher birthrates and cub survival.

    More young animals breed in situations of social disruption that are caused by the beheading of the pack.

    Growing cubs require more food than mature animals.

    Just throwing this out there.

  • 2. EmilyS  |  October 29, 2009 at 9:59 pm

    of course the wolf hunt really has little to do with limiting their predation on elk, anymore than the bison hunt has to do with controlling brucellosis…

  • 3. mongo  |  October 29, 2009 at 11:54 pm

    Hmmm…..found this online from last year- doesn’t sound like anyone is all that excited about a inventing criteria for a “trophy wolf”….
    http://trib.com/news/state-and-regional/article_bfed5a4e-bb72-50d1-875e-3005df44db1b.html

  • 4. mongo  |  October 30, 2009 at 8:19 am

    Hmmm…..found this online from last year- doesn’t sound like anyone is all that excited about a inventing criteria for a “trophy wolf”….
    http://trib.com/news/state-and-regional/article_bfed5a4e-bb72-50d1-875e-3005df44db1b.html
    Sorry, forgot to add great post! Can’t wait to see your next post!

  • 5. retrieverman  |  October 30, 2009 at 2:01 pm

    The same thing most likely happened to us when we lived as wolf-apes hunting the big game.

    The average lifespan for a person in the Upper Paleolithic was 33, which is actually longer than it was for most of our history as an agricultural species.

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