A snake is not a mammal; it belongs to a separate biological grouping of vertebrates. Snakes are classified within the Class Reptilia, while mammals are in the Class Mammalia. This distinction is based on unique characteristics that define each group, covering everything from skin covering to how they regulate their internal temperature.
Defining the Mammal Class
The Class Mammalia is defined by a specific suite of biological criteria. One defining characteristic is the presence of mammary glands, which produce milk to nourish the young after birth. All mammals exhibit hair or fur at some stage of their life cycle, which provides insulation and helps with sensory input and communication.
Mammals are endotherms, meaning they generate and regulate their own internal body heat through metabolic processes. This allows them to maintain a stable body temperature regardless of the external environment. The mammalian skeletal structure also features unique specializations, including a lower jaw composed of a single bone and three small bones in the middle ear: the malleus, incus, and stapes.
They also possess a muscular diaphragm, which plays a role in efficient lung ventilation for respiration. This high metabolic rate and specialized anatomy supports the active lifestyle many mammals lead across diverse global habitats.
The True Classification of Snakes
Snakes are classified within the Class Reptilia, a group that also includes lizards, turtles, and crocodiles. A defining characteristic of reptiles is that they are ectotherms, meaning they rely on external sources of heat to regulate their body temperature. Their internal temperature fluctuates with the temperature of their surroundings.
The skin of a snake is covered in overlapping horny scales or scutes, which are made of keratin. This dry, scaly skin is impermeable and helps to prevent water loss, an adaptation for terrestrial life. While many reptiles lay eggs, snakes display varied reproductive strategies, with some species laying amniotic eggs and others giving live birth.
Even in species that give live birth, the young are not nourished by milk, as reptiles lack mammary glands. The snake’s anatomy also differs significantly from mammals, possessing a lower jaw made up of several bones and having only a single bone, the stapes, in each ear. Snakes belong to the suborder Serpentes, a group of elongated, limbless reptiles.
Key Biological Differences
The most fundamental difference lies in thermoregulation. Mammals are endotherms, constantly burning energy to keep their body temperature stable and remain active in diverse climates. Reptiles, including snakes, are ectotherms and must behaviorally seek out heat sources, such as basking in the sun, or cool areas to maintain their optimal temperature.
The integument, or outer covering, provides another clear distinction: mammals have hair or fur, which is an insulating layer tied to their endothermy. Snakes are covered in dry, keratinous scales, which primarily serve as a protective barrier against water loss and injury.
Mammals possess mammary glands to produce milk, providing a high level of parental investment immediately after birth. Snakes have no such glands, and while some exhibit parental care, it does not involve the post-natal nutritional support seen in mammals.