Like all groups of reptiles, snakes have the following characteristics:
- Cold-blooded -Snakes are ectotherms, and unlike mammals they do not rely on cellular metabolism to maintain their temperature. Instead they obtain their heat from external sources, such as the sun. Some species of snakes can go up to 12 months without eating and as a result can live in areas where food is not plentiful.
- Scales - Snakes are covered in scales. Their scales work similarly to that of a raincoat, instead of not letting water in, scales don't let water out. This prevents them from dehydrating and as a result enables them to colonise very arid regions such as deserts.
- Sloughing - Snakes simultaneously shed their outer layer of skin intermittently, which is usually directly related to growth rate.
- Sexual dimorphism - Female snakes and male snakes are very difficult to differentiate because all of their reproductive organs are internal.
- Growth - Reptiles are the only group of vertebrates (animals with backbones) that continue to grow throughout their life.
- Food - Snakes feed on a variety of prey including mammals, birds, reptiles, amphibians, fish and invertebrates. All food items are eaten whole.