The familiar ecological roles for mushrooms are as helping trees grow in a symbiotic relationship with their roots, and then living on decaying wood and thereby helping to break it down. But they also have relationships with animals.
They are a food source. A surprising number of mammals love a tasty mushroom, like this woodchuck:
and this chipmunk, who has carefully folded a large one in half to make for easier carrying, complete with a sort of dead leaf sandwich filling.
Squirrels store them for the winter by perching them up in trees to dry, which may be what gave the Italians the inspiration for dried porcini.
But the great cycle of life goes on, and some mushrooms thrive on the by-products of mammals, poop. This is bear poop, and it is entirely covered in a pale blue fungus called Penicillium vulpinum .
Here it is in close-up:
In a rather disconnected leap, inspired by the notion that another by-product of mammals is milk, this slime mold fungus rejoices in the name of Wolf’s Milk, Lycogala epidendrum.
If you puncture a young specimen, out oozes an orange gluey substance, which I suppose must be the source of its name. Since I am fairly sure that actual wolf’s milk is white, it doesn’t explain much. But it certainly has a whiff of Halloween to it, so maybe we should think of werewolves?
PS Thanks to Leigh Hayes for the ID of the blue fungus on the bear poop!