Yes, a skate is a type of fish. Skates belong to the cartilaginous fish group, which includes sharks and rays.
What Defines a Fish
Fish are aquatic vertebrates, meaning they possess a backbone and live in water. They breathe using gills, which extract oxygen from the water as it passes over specialized tissues. Fins aid movement and steering.
Fish are divided into two main groups based on skeletal structure. Bony fish (Osteichthyes) have skeletons primarily composed of bone. They have a protective bony flap called an operculum covering their gills and a swim bladder for buoyancy control.
In contrast, cartilaginous fish (Chondrichthyes) possess skeletons made of cartilage, a flexible tissue. Sharks, rays, and skates fall into this group. Unlike most bony fish, cartilaginous fish have multiple gill slits that open directly to the outside and lack a swim bladder, relying on other mechanisms for buoyancy.
Skates: Unique Cartilaginous Fish
Skates are cartilaginous fish with specialized features. Their bodies are flattened, appearing rounded or diamond-shaped, with large, wing-like pectoral fins extending from their head to their slender tail. These fins are used for propulsion, allowing them to glide along the seafloor.
Their gill slits, usually five pairs, are located on the underside of their body, along with their mouth. This ventral arrangement is an adaptation for their bottom-dwelling lifestyle. Skates also have small openings called spiracles behind their eyes on their dorsal surface, which allow them to draw in water for breathing even when partially buried in sediment.
Skates are oviparous, laying eggs. These eggs are encased in tough, leathery capsules known as “mermaid’s purses,” often found washed ashore. This method distinguishes them and highlights their ties to cartilaginous fish.
Distinguishing Skates from Rays
While skates and rays share many similarities as flattened cartilaginous fish, key differences distinguish them. One apparent distinction lies in their tails. Skates have thicker, fleshier tails that may feature small fins and thorny projections but lack stinging barbs.
In contrast, many rays possess whip-like tails that are often longer and thinner than those of skates. Some ray species, like stingrays, have one or more venomous barbs located on their tails for defense. This difference in tail structure is a reliable indicator for identification.
Reproductive methods also differentiate them. Skates are oviparous, laying their young within protective “mermaid’s purses” on the ocean floor. Rays, however, are typically viviparous or ovoviviparous, meaning they give birth to live young that develop inside the mother’s body.
Beyond these features, general body shape can offer clues; skates are more triangular or rounded with a distinct snout, while many rays exhibit a more diamond-shaped disc. Although both groups are bottom dwellers and share similar diets, these specific anatomical and reproductive traits are important for accurate classification.