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Beaver Scent Mounds

4-30-13 beaver scent moundsThis is the time of year when two-year-old beavers leave their lodges and strike out on their own, primarily because the woods surrounding a pond usually can’t support more than one family of beavers. Beavers are exceptionally territorial; once they’ve established a lodge, they do not take kindly to interlopers. In order to make this perfectly clear to house-hunting young beavers, in the spring resident beavers build what are called scent mounds — piles (up to three feet in height, but usually much smaller) of mud, leaves and pond-bottom debris — around the perimeter of their territory. They then smear castoreum, a substance that comes from their castor sacs, over the mound. Chemicals in the castoreum convey to roaming young beavers that this particular pond is spoken for.

5 responses

  1. Donald Patterson

    Mary, My cousin, being plagued by beavers, also refers to these as castor mounds. Don

    Sent from my iPhone

    April 30, 2013 at 11:11 am

  2. Connie Snyder

    I am forwarding this interesting post to the teachers at Thetford Elementary who regularly take their second-graders to the beaver habitat at Upper Valley Land Trust’s Zebedee Wetlands. Your work helps us all see more. Thank you. Connie Snyder

    April 30, 2013 at 12:49 pm

    • Thank you so much for making the teachers in Thetford aware of my blog, Connie. I love knowing it’s shared with youngsters. Mary

      May 2, 2013 at 10:24 pm

  3. Ryan

    I remember reading somewhere (I thought it was from you but I couldn’t find it) that resident beavers will also use these scent mounds to indicate whether they have a mate or are seeking one. Is this a function of the mounds as well?

    May 2, 2013 at 1:36 am

  4. Ryan,
    Everything I’ve read and heard associates castoreum/scent mounds with territorial marking, but it wouldn’t surprise me a bit if there were pheromones that communicated the age/availability of the marking beaver as well!

    May 4, 2013 at 9:19 pm

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