Deserts are known to be hot, dry biomes. But there are also "cold" deserts. In these deserts the nights are very cold, especially in the winter. As there is little rainfall, few types of plants exist. Some vegetation includes cactus and the Joshua tree. Animals in the desert include marmots, prairie dogs and several varieties of snakes and lizards. Many of these animals live underground for much of the day. They adapt to the heat by hiding under rocks when the sun is out.