Snakes are elongated, legless reptiles. Understanding their biological classification provides insight into their evolutionary history, unique adaptations, and relationship with other animals. This framework helps to organize the vast diversity of snake species found across the globe.
Snakes in the Animal Kingdom
They belong to the Kingdom Animalia. Within this kingdom, snakes are part of the Phylum Chordata, characterized by the presence of a notochord at some stage of development.
Snakes fall under the Class Reptilia, a group of vertebrates distinguished by scaly skin, lungs for breathing, and the laying of amniotic eggs. The Order Squamata includes both lizards and snakes, sharing a movable quadrate bone in the skull that allows for jaw flexibility. Finally, snakes are exclusively categorized within the Suborder Serpentes.
Defining Snake Characteristics
Their most recognizable feature is a legless, elongated body. This body plan is supported by an incredibly flexible spine composed of hundreds of vertebrae, enabling their characteristic slithering movement.
The skin of a snake is covered in overlapping scales that provide protection and aid in movement. These reptiles are ectothermic, meaning they regulate their body temperature by absorbing heat from their environment. A highly specialized jaw structure with loosely connected bones allows them to swallow prey much larger than their heads. Snakes lack external ears and eyelids, instead having transparent scales, called spectacles, covering their eyes.
Distinguishing Snakes from Other Reptiles
While snakes are limbless, they differ from other legless reptiles, particularly legless lizards. A primary difference lies in the presence of eyelids and external ear openings; most legless lizards possess these features, whereas snakes lack both.
Snakes possess a forked tongue used to collect chemical cues from the environment, which they process with a specialized Jacobson’s organ. While some lizards also have forked tongues, legless lizards typically have notched or rounded tongues. The jaws of snakes are significantly more flexible, allowing them to dislocate and independently move their jawbones to consume large prey, a capability most legless lizards do not share. Legless lizards often have a body where a significant portion is tail, making their bodies feel more rigid than the fluid, muscular body of a snake.
Major Snake Families
The Suborder Serpentes encompasses a wide array of snake diversity, organized into several major families. The Colubridae family is the largest and most diverse, including many common non-venomous snakes such as kingsnakes, corn snakes, and garter snakes.
The Elapidae family is another prominent group, which includes highly venomous snakes like cobras, mambas, kraits, and coral snakes, characterized by fixed front fangs. The Viperidae family consists of vipers and rattlesnakes, known for their hinged fangs that fold back when not in use. Large constrictors like boas (Family Boidae) and pythons (Family Pythonidae) represent significant snake families, though some classifications may group them differently.