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Female Winter Ticks Dropping Off Moose & Laying Eggs

One of the many injurious effects of climate change is the increase in Winter Ticks (Dermacentor albipictus) due to warmer New England winters.  These parasites spend their entire lives living off of one host and they have had a major impact on the moose population, especially on calves. Research conducted by the University of New Hampshire over a three-year period found that moose calves suffered a 70 percent death rate as a result of winter ticks.


At this time of year, when moose are at their most vulnerable, adult female ticks living on them, most of which are gravid (the ticks), indulge in a “blood meal” that is unlike any of the meals that they take at any other stage of life. They feed for days, swelling to ten times their normal size before dropping to the ground and laying hundreds of eggs.  The snow where a tick-infested moose has laid down is often spotted with blood and engorged female ticks. It may be of some comfort to know that Winter Ticks rarely bite and feed on humans. (Photo: A moose calf that had been walking along a packed snowmobile trail laid down , leaving spots of blood from tick bites and many 1/2″-long engorged and egg-filled female ticks.)  Thanks to Kit Emery for photo op.

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8 responses

  1. Don mccabe

    We spotted our first deer ticks yesterday on our golden retriever’s head, All it took was a short walk in the woods.

    March 16, 2020 at 5:28 pm

  2. Alice

    That 70% number is so sad. How disgusting to see bloody ticks lying on the snow.

    March 16, 2020 at 5:44 pm

  3. Just read about a potential fungal solution to this problem in Northern Woodlands. I desperately hope it’s effective.

    March 16, 2020 at 5:49 pm

  4. hellomolly

    How disgusting! So awful that moose are carrying such an enormous tick load.

    March 16, 2020 at 5:59 pm

  5. Su

    Ugh…too sad…too much on top of the COVID news. Do you have any “hope springs eternal” posts coming soon? I hope (she says springing eternally)

    March 16, 2020 at 6:14 pm

  6. Wow. How terrible that humans’ unsustainable choices have led to this painfully sad situation for these fellow inhabitants of the northern forests. I’m curious about the “potential fungal solution” mentioned by Kellyann, above. I’ll guess I can look in Northern Woodlands. Thanks for this troubling but informative post, Mary. In so many ways these are anything but ordinary times. May we find ways to ‘come together’ in spirit, to support each other and to take action to protect the natural world that is our true home. (That’s the hope I hold onto, along with the lifting up that comes on such a delightful spring day as this one!)

    March 16, 2020 at 6:38 pm

  7. Bill on the Hill

    Thanks Mary… No doubt, a sad plight for our largest member of the deer family. I have seen pictures of moose completely covered in ticks as they die a very slow death.
    Currently not the happiest of subjects with respect to the ” dark cloud ” hanging over the heads of us all…
    However, we will get through this, we always do…
    Bill on the Hill,
    Vermont… :~)

    March 17, 2020 at 8:21 am

  8. Barbara Bloomberg

    I have seen this type of scene, and wondered if the ticks would die if frozen? The ones I spotted were frozen solid, on a frigid spring day.

    March 19, 2020 at 6:01 pm

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