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Black Bears Foraging

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This is the time of year when Black Bears are looking for every available source of food in order to bulk up before entering hibernation. During this period of gorging (hyperphagia) Black Bears consume large quantities of fruits, berries, nuts, grasses, roots and insects.

In particular, they favor the brood (larvae and pupae) of ants, due to their relatively high content of fat and protein. Black Bears find brood by detecting the pheromones and other chemicals such as formic acid that ants use for communication and defense. Research has confirmed that Black Bears will dig up as many as 200 ant colonies a day, flipping rocks, moss and leaf litter over and tearing apart logs, stumps and snags (such as the one pictured), using their canine teeth and claws to gain access to the ants. Once they have torn apart the stump or snag, they use their long, sticky tongues to gather brood. Anthills are avoided except for when Black Bears are extremely hungry, due to the fact that bears prefer not to get a lot of soil or sand mixed in with the brood they’re eating. (Thanks to Virginia Barlow for photo op.)

7 responses

  1. Gordon W. Gribble

    Because formic acid is not very volatile, I wonder if the bears are detecting the ant trail pheromones, which are volatile (i.e., ketones like acetone or paint thinner). We know that ant eaters have adopted this tactic.

    September 6, 2017 at 8:35 am

  2. Alice Pratt

    Kinda interesting that Big Bears crave such Little Beasties! Again, I’m so glad we don’t have Bears here (yet😕)…. Coyotes are enough, as they were making such a ruckus a few nights ago.

    September 6, 2017 at 8:36 am

  3. Mark Dindorf

    Hi Mary,

    Last week I sent you a couple of pictures and a question about some piles of rocks I saw in a river in Western Maine while kayaking. Wondering if you received my email and if you have any ideas about what formed the rock piles. I sent it as a reply to your blog post with two photo attachments on the day you posted about grasshoppers molting.

    Any insights you have would be gratefully appreciated.

    Mark Dindorf Hart’s Location, NH

    Sent from my iPhone


    September 6, 2017 at 11:11 am

    • Hi Mark,
      I replied to your comment that day, but you must not have gotten it. WordPress does not allow photos to come through, so if you want you can email them to me at I don’t immediately know what the piles might be, but could pass on your photos to someone who might!

      September 6, 2017 at 11:55 am

  4. Just discovered your blog. It is fascinating. Thanks so very much.

    September 6, 2017 at 7:40 pm

  5. I’ve seen many more shredded snags and logs lately than in past years. Several in our community have been concerned by the number and size of bears roaming various neighborhoods in the past couple of weeks. As a newby living full-time in bear country, I’m assuming this is a peak time for their visible presence. My husband found a huge scat at the top of our mowing this week containing pits the size of peas throughout it. We can’t figure out what plant it might have been eating…I’ll email you his photo.

    While we’re admiring our local animals who earnestly prepare for winter, let’s all wish safe passage to the thousands of migrants who are heading south into the fury of oncoming storms!

    September 6, 2017 at 9:46 pm

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