How a Chipmunk Baby Boom Leads to More Mushrooms

When I went out to look for edible mushrooms in a stand of oaks, beech, and hemlocks recently, I found uprooted, overturned, and torn-apart mushrooms everywhere. It looked like a tiny hurricane had targeted only the fungi.

ripped and scattered mushrooms on forest floor

A closer look revealed rodent toothmarks. Small mammals like chipmunks and red squirrels feed on mushrooms; the scene of destruction might be explained by this year’s chipmunk baby boom, which was spurred by high seed production in oaks and beeches in 2019.

teethmarks on wild mushroom

Beechnuts and acorns aren’t as plentiful this year, driving chipmunks to seek out alternative foods like fungi, which supply fiber, protein, complex sugars, vitamins, and immune-boosting compounds.

Seeing this led me to a research paper that shows how mushroom-eating chipmunks play an important role in helping the forest regenerate.

Like apples on a tree, mushrooms are the reproductive part of a larger fungi structure that runs all through the ground and helps nourish tree roots. The spores produced by mushrooms can survive the trip through a chipmunk’s digestive system and get deposited in its scat, often far from the site of the original mushroom meal. Spores grow into new fungal organisms, which get established at the same time all of those acorns and beechnuts from last year are growing into seedlings.

spores on chipmunk eaten mushroom

It really is all connected. Trees produce extra seeds, extra seeds mean extra chipmunks, and extra chipmunks are forced to eat fungi, which they then disperse widely to strengthen fungal communities in the soil and support the growth of new trees from the seeds the chipmunks didn’t devour.

The best part, though, is that the chipmunks seemed to stay away from my favorite edible mushroom — black trumpets!

(Note to readers: Please be very careful about eating mushrooms in the wild as many are poisonous!)