Snakes are a diverse group of reptiles found across nearly every continent. Their evolution has resulted in unique sensory, feeding, and growth mechanisms that allow them to thrive in varied environments. This article will explore three specific facts about their biology.
Sensing the World with the Tongue
A snake’s constant tongue-flicking is not a sign of aggression but a sophisticated method of gathering environmental information. The forked tongue does not function for taste, but acts as a mobile collector of airborne chemical particles. These scent molecules adhere to the damp surface of the tongue as it flicks out and retracts.
The tongue then delivers these collected particles directly to a specialized sensory organ, known as the vomeronasal organ, or Jacobson’s organ, located in the roof of the mouth. This organ analyzes the chemical data, allowing the snake to “smell” its surroundings. The split tip of the tongue allows the snake to detect a chemical gradient, sensing if a scent is stronger on the left or the right tip. This provides the animal with a directional, or stereo-sense of smell, enabling it to pinpoint the exact location of prey or a mate.
The Jaw Mechanism
Snakes are famous for consuming prey much wider than their own heads, an ability often mistakenly attributed to “unhinging” their jaws. The mechanism involves a highly flexible skull structure. Unlike a human lower jaw, which is fused at the chin, the two sides of a snake’s lower jaw are connected by an elastic ligament.
This ligament, along with multiple movable joints in the skull, permits the lower jaw bones to separate and stretch significantly around large prey. The snake then employs a technique known as “walk feeding,” where the left and right sides of the jaw move independently. One side holds the prey steady while the other side stretches forward, ratcheting the food down the throat in a slow, alternating movement.
Shedding Skin for Growth
Snakes periodically shed their entire outer layer of skin through a process called ecdysis, which is essential for growth and health. Shedding allows the snake to accommodate its increasing body size since the skin does not stretch indefinitely. The process also removes external parasites, like mites, and repairs worn or damaged scales.
Just before shedding, a layer of fluid builds up between the old and new skin, which causes the snake’s clear eye scales (spectacles or eye caps) to take on a milky or cloudy blue appearance. This temporary “cloudiness” indicates that shedding is imminent, and vision is often impaired during this stage. When the shed is successful, the old skin is typically peeled off in a single, complete tube, often including the clear eye caps.