(pl. squirrels)
Terms discussed: acorn
Topics:
Acorn truffles
Squirrels and mushroom poisoning
See Also:
Truffle
Acorn truffles
Acorn truffles are underground fungi that look (and smell) a bit like acorns. Squirrels find them, mistake them for something they buried last Fall, and eat them, distributing the spores once they pass through the squirrel's digestive tract. Other underground fungi also have their spores distributed by animals that eat the fruiting bodies. Acorn truffles are actually "true truffles", species of the genus Tuber, but don't have the powerful smell and flavor of their more famous relatives. Nor are squirrels the only animals that do this - - the California red-backed vole lives exclusively on truffles and other hypogeous fungi. Maybe good mycologists come back as red-backed voles...
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Squirrels and mushroom poisoning
According to Dr. John Rippon, an IMA member and world expert on fungal diseases, squirrels have an interesting adaptation that allows them to eat mushrooms containing deadly amanita-toxins without being affected. There are three important chemicals in the amanitas. Two will knock you right off, but are destroyed in cooking. The third one is the interesting one: it consists of the second amanitin, bound tightly to a glycoprotein molecule. When we digest the mushroom, the enzymes in our gut break the bond between the toxin and the glycoprotein, leaving the toxin free to enter our bloodstream, while the glycoprotein is excreted (a glycoprotein is a mucus molecule, in case you don't know). What the squirrels have done is line their gut with a toxin-compatible glycoprotein, so that as soon as it gets split from its original glycoprotein molecule, it gets rebound to the squirrel glycoprotein, and excreted along with it. Obviously, the squirrels don't cook their food to destroy the first two molecules, but presumably those get bound in exactly the same way. Thus, squirrels and a few other animals (guinea pigs also, I believe) can eat mushrooms that are highly toxic to other animals with no ill effects.
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