Certain small mammals eat a large quantity of truffles. They are attracted by the truffles' pungent odor, and either dig them up to carry home or tunnel underground from truffle to truffle. Spores from the truffles pass through the digestive system of these animals and the spores are left to inoculate seedlings of the host species. This is the only known way the spores of many of these highly adapted fungi can be dispersed. All known truffles function in mycorrhizal associations with plants.
Some trees require the truffle associate for establishment and survival.
In the early 1800s, once the association between truffles and its mycorrhizal host species, the oak, became known in Europe, fields of oaks were planted specifically for truffle production. In the Pacific Northwest, truffles are a relatively untapped source of wild food.