Snakes are specialised limbless reptiles, most closely related to lizards. Ranging in size from around ten centimetres to over ten metres, snake body shape and length varies greatly depending on each species’ lifestyle and diet. Snakes are found in a wide range of different habitats and are able to move over land, climb, swim or burrow with ease.
Snakes typically have poor eyesight and hearing but are able to detect their surroundings using other senses. By flicking its tongue, a snake is able to pick up scent molecules which are analyzed using a special organ known as Jacobson’s organ. Some species have heat sensitive pits in the scales around their mouth which can help them to detect warm-blooded prey.
Snake skin is covered in separate scales and topped with a tough layer of keratin for added protection. As this keratin can become worn or damaged and does not allow for growth, snakes must shed their skin from time to time. Snakes typically shed most often when they are young, and also after hibernation and before and after giving birth or laying eggs. Unlike lizards, snakes shed their skin in one piece, including the eye caps. Check out this video of a grass snake (Natrix natrix) shedding its skin.
All snakes are carnivorous, and are skilful predators which feed on prey ranging from small insects to crocodiles. Some snakes actively chase prey while others use stealth to ambush their unsuspecting victims. Small prey can often be swallowed alive and whole, but when tackling larger animals, snakes may employ a venomous bite or constricting embrace to subdue or kill their quarry before it is consumed.
Snakes are well known for their ability to swallow large prey, thanks to their inward pointing teeth, unfused lower jaw and extremely flexible skin. Eating such large meals means that some species need to feed less than once a month, and some pythons and boas can survive for a year or more without eating.
Although venomous snakes are among the most famous and the most feared, only a small proportion of snakes are actually venomous, and many of these pose no threat to humans. Snakes are reactive rather than aggressive and will typically only bite when threatened. Venom comprises of modified digestive juices that not only subdue or paralyze the prey animal, but also begin to digest it, breaking down the skin and internal organs. Some species of snake use venom defensively, such as the Mozambique spitting cobra (Naja mossambica).
While most snakes lay eggs, there are also a number of species which give birth to live young. Although very few snake species show any level of parental care, there are a small number of species such as pythons, in which the female will coil around the eggs to guard them from predators and possibly help to incubate them too. Although nearly all snakes reproduce sexually, there are a few which can reproduce through parthenogenesis, meaning that all members of the species are female and have hatched from unfertilised eggs. One such example is the Brahminy blind snake (Ramphotyphlops braminus).