Eels are often mistaken for snakes due to their elongated, serpentine bodies. Despite their similar appearance, eels are fish, not snakes, with fundamental biological differences.
Eels: True Fish, Not Reptiles
Eels are classified as fish, belonging to the order Anguilliformes. Like all fish, they possess gills, allowing them to extract oxygen directly from water and breathe submerged. This adaptation is fundamental to their fully aquatic existence. Eels also have fins, though these can sometimes be reduced or fused, contributing to their snake-like look. They possess a backbone, classifying them as vertebrates. Their life cycle and physiology are entirely adapted for an aquatic environment.
How Eels Differ From Snakes
A primary distinction between eels and snakes lies in their respiratory systems. Eels rely on gills to breathe underwater, extracting dissolved oxygen from their aquatic surroundings. In contrast, snakes, being reptiles, possess lungs and must surface to breathe air.
Their body coverings also differ. Eels typically have smooth, slimy skin, often with very small, deeply embedded scales. Snakes, however, are covered in dry, overlapping scales that provide protection and aid in movement across various terrains.
Eels are characterized by their fins, which are used for propulsion and steering in water, even if these fins are sometimes subtle or fused into a continuous structure. Snakes, on the other hand, are limbless reptiles, moving by muscular contractions and specialized scales on their undersides.
Their reproductive strategies also vary. Eels typically lay eggs in water or give live birth to larvae in aquatic environments, while snakes lay shelled eggs on land or give birth to live young on land.
Eels are primarily aquatic creatures, inhabiting a wide range of freshwater and marine environments. Snakes, while some are semi-aquatic, are predominantly terrestrial, living on land.
Their jaw structure also differs. Eels have relatively fixed jaws, designed for grasping prey. Snakes possess highly flexible jaws that can disarticulate, allowing them to swallow prey much larger than their head.
Eel Diversity and Habitats
The world of eels is remarkably diverse, encompassing over 800 known species that thrive in various aquatic environments. This group includes freshwater eels, which undertake extensive migrations between rivers and the ocean. Marine eels, like moray eels, are common inhabitants of coral reefs and rocky crevices in the ocean. Other notable examples include the electric eel, which is actually a type of knifefish rather than a true eel, known for its powerful electrical discharges. Eels occupy a broad spectrum of habitats, ranging from shallow coastal waters to deep ocean trenches, freshwater lakes, rivers, and even underground caves.