Desert organisms must be able to adapt to extreme daily fluctuations in temperature, from cold in the evenings to scorchingly hot during the daytime hours. They must be able to survive in a harsh environment where water is a limiting factor. Cacti and succulents found in this biome can store moisture in the sap in their stems. They usually have a waxy cuticle to keep water within the plant. The leaves of cacti are reduced to spines, limiting their surface area and amount of stomates. This in turn, helps retain water inside the plant. Roots are shallow and spread out near the surface. In the event it does rain briefly, those roots will quickly absorb water before it evaporates. Animals in the desert can use behaviors as adaptations. Many are nocturnal and seek shelter in burrows out of the direct sunlight during the daytime hours. Kangaroo rats can survive where there is almost no water and yet, their bodies contain the same amount of water as other organisms. They can convert dry seeds into water, have specialized kidneys which waste very little water and only come out in the evenings when it is cool outside. Besides mammals like the kangaroo rat, other animals found in the desert include: arachnids, birds, insects, reptiles and amphibians. Each is uniquely adapted to life in this harsh environment.