They have been collected for at least 3600 years. Growing underground, they are difficult to find and very expensive as a result. Every Spring, truffle hunters in Europe take to the woods, hoping that the sensitive noses of their trained pigs and dogs will lead them to buried treasure. Real truffles are roundish, brown, and dirty when they come out of the ground. They are the fruit of the truffle organism, like apples are the fruit of an apple tree.
Truffles contain spores for reproduction the way an apple contains apple seeds.
Many animals can easily reach fallen apples, and so spread their seeds by way of uneaten cores, or in dung. Squirrels and chipmunks dig up truffles in the same way they may steal flower bulbs in your garden. They are the major wild animals dispersing truffle spores in North America. In return, the tree host provides the fungus with carbohydrates and other nutrients, the product of the tree's photosynthesis. Attempts are being made to farm truffles due to the difficulty in finding them in the wild.