For much of the year, the truffle organism is nothing more than a network of rootlets, fine as hair, that spreads among the tree roots. Then, in response to seasonal or weather-related triggers, the truffle organism produces a fruiting body, the part we eat. There is no consensus on what prompts the fruiting bodies to form. Ancient Romans believed that truffles were materialized by lightning strikes, and modern-day Bedouin still do. The heavy rain that accompanies thunderstorms is a better explanation, although temperature and other factors probably come into play as well. The fruiting body contains spores, the fungal equivalent of seeds, and as the truffle matures after several months of growth, it releases an aroma to attract animals. The animals dig it up to eat, scattering spores to generate the next generation of truffles. Conscientious truffle hunters will scrape clean a freshly dug truffle and put the spore-rich dirt back in the hole. A lot of hunters also follow the lunar calendar, believing that the harvest peaks at the full moon.