Skate Fish vs. Stingray: Comparing Bottom-dwelling Fish

If you're lucky enough to find a leathery black rectangle with curling tendrils on the ocean floor, you've spotted a skate's egg case, often called a mermaid's purse. These egg cases protect developing embryos in a strategy called oviparity.

Skates lay eggs, and many species use this reproductive method. Some species produce multiple mermaid's purses at once, anchoring them to the seafloor.

Stingrays, on the other hand, give birth to live young — a quality called viviparity, or live birth. This internal development shields young rays from predators before they're ready to swim.

These reproductive strategies distinguish the two groups from each other and from many other marine species.

A skate fish has a thick tail with two lobes, resembling a short rudder. These tails often have thorny projections, sharp spikes, or small fins for steering along the sea floor. The two-lobed tail lacks a stinging barb, making physical armor and camouflage essential for protection.

Stingrays, by contrast, have whip-like tails. A stingray's tail often ends in one or more venomous barbs. This stinging spine can deliver a nasty sting if provoked.

In fact, the pain from a stingray injury is notorious in marine circles. Their nasty sting serves as a primary defense mechanism, especially against natural predators like sharks.

Both fish have large, wing-like pectoral fins that fuse with their head and extend out to form a diamond-shaped or disc-shaped body.

Their pelvic fins differ: Skates have two lobes, while stingrays belong to the one lobe group.

Dorsal fins add more clues. Stingrays typically have small or absent dorsal fins, while most skates have more prominent ones. Though there's no hard and fast rule, these features often help in identification.

Skates have pointed teeth for gripping small fish, worms, and other prey. These teeth help them seize and hold agile prey along the ocean floor.

Stingrays tend to target hard-shelled prey like mollusks and crustaceans. Their broad, plate-like teeth specialize in crushing prey. They're experts at crushing hard-shelled prey, breaking open clam and oyster shells with jaw strength alone.

Though both stick close to the bottom, they occupy different zones. Skates are most often found in deep water, at depths greater than 200 meters, favoring cold, stable conditions. Their physiology is well-adapted to deep water pressure and low temperatures.

Stingrays, meanwhile, prefer shallow waters like coral reefs, lagoons, and estuaries. These warm, food-rich environments make them a staple sight for snorkelers and divers.

Both groups breathe through gill slits, usually five on each side, located on the underside. This ventral placement is a shared trait among benthic animals — species that live on the seafloor.

They’re all cartilaginous fish, meaning their skeletons are made of cartilage instead of bone. That puts them in the same broad category as sharks and rays.

But unlike sharks, skates and stingrays don’t slice through open waters. Instead, their flat bodies keep them hugging the sea floor, out of sight and often buried in sand.

There are different species of skates and stingrays, with various sizes, colors, and patterns adapted to specific ecosystems. Some are incredibly rare and considered vulnerable species due to habitat loss and overfishing.

Their natural predators include large fish, sharks, and humans. While stingrays have their stinging barbs for defense, skates rely more on camouflage and thorny projections for defense. Their ability to avoid detection is often more critical than confrontation.

As benthic dwellers, skates and stingrays help regulate populations of prey like crustaceans and mollusks. Their feeding habits affect the distribution of hard shelled prey and small fish alike. By consuming other prey, they balance ecosystems on the sea floor.

They also serve as food for larger predators, making them a vital part of the oceanic food chain. Their defense mechanisms — from venomous barbs to thorny projections — are adaptations to life in predator-heavy waters.

Here’s the last difference you might not notice unless you’re watching them swim. Stingrays tend to undulate their entire bodies like a ribbon when they move. Skates, however, flap their pectoral fins like wings.

These contrasting movement styles are one more way to tell these animals apart in the wild.

We created this article in conjunction with AI technology, then made sure it was fact-checked and edited by a HowStuffWorks editor.