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Discerning Eastern Gray Squirrels

1-3-14 gray squirrel2 029In the fall, Eastern Gray Squirrels bury individual acorns from Red and White Oaks to sustain themselves through the winter. The acorns of Red Oaks have delayed germination – they can be stored up to six months before they start germinating. The acorns of White Oaks, however, have no such dormancy, and begin to germinate in the fall, soon after they fall from the tree. Once acorns sprout, they are less nutritious, as the seed tissue converts to the indigestible lignins that form the root. Gray Squirrels, as a means of “long-term cache management,” selectively remove the embryos from White Oak acorns (but not from Red Oak acorns) before burying them. Germination is prevented, and the storage viability of the White Oak acorns is extended by six months, equaling that of the Red Oak acorns.

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6 responses

  1. That is so interesting, I had no idea. I wonder how long and how many generations it took for that adaptation to take hold? Nature is amazing!

    January 3, 2014 at 3:23 pm

  2. betsy stewart

    well We always knew they were smart – but that takes the cake / acorn.

    January 3, 2014 at 3:45 pm

  3. Jean Harrison

    Amazing! Almost unbelievable — but I do.

    January 4, 2014 at 5:57 am

  4. I am curious if their is a research paper that outlines or documents this activity? Another unknown fact within this plant family, the Fagaceae, is that the oak flower once had the capacity to produce 5 acorns per flower. Through time, this was reduced to 3 per flower, perhaps less, but more viable (stronger acorns – more storage capacity) emerged as an advantage?

    January 8, 2014 at 6:29 pm

    • Hi Tim,
      Work was cited in The Biology of Small Mammals by Merritt giving credit to M.A. Steele et al. “The innate basis of food-hoarding decisions in grey squirrels: Evidence for behavioural adaptations to the oaks. Anim. Behav. 71:155-160.

      January 8, 2014 at 9:17 pm

      • Thanks! I have an oak talk coming up and will share this!

        January 8, 2014 at 9:19 pm

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