Sea Watch: Electric Rays

The electric ray is one of those creatures that might have simultaneously fascinated and frightened you as a child. Lurking unseen on the seafloor, it has the power to send a jolt of painful electricity rippling through your body. The mechanism that provides this power is unique, emanating from kidney-shaped organs made of striated muscle located on either side of the ray’s head. These modified muscles contain columns of electrocytes — jelly-filled electric plates, kind of like rows of batteries — that electric rays use to generate their charge.

pacific electric ray

Noam Kortler

The Pacific electric ray is found off the coast of California.

atlantic electric ray

NHPA/Photoshot/Superstock

The Atlantic’s beautiful common torpedo ray belies its pedestrian name.

There are many varieties of the electric ray. In the United States, one common type is the Pacific electric ray, found off the California coast. These rays are part of the Torpedinidae family, commonly called torpedoes — which is where we got the name for the weapon — that includes 22 species around the world. The Pacific electric ray can grow fairly large, about 4 feet long, and generates about 45 volts of electricity, which it uses for self-defense and to stun its prey.

The Pacific electric ray’s cousin on the East Coast is called the Atlantic torpedo, and it’s even larger, growing up to 6 feet long and nearly 200 pounds. These behemoth blasters pack the largest punch of any electric ray, producing up to 220 volts of electricity.

The Atlantic torpedoes can be found in coastal waters on both sides of the Atlantic, though they prefer cooler water so are more often seen in locations such as New England and the Mediterranean Sea.

There’s a second family of electric rays called Narcinidae; the main difference between the two is how they give birth, not how they deliver their electrical payload. The name Narcinidae — and its common name, numbfish — comes from the ancient Greeks, who used the rays as a form of anesthesia because of the localized numbing sensation that their shock left behind.

Numbfish are found all over the world; they are not only smaller than the torpedoes — only about 2 feet at the largest — but they also deliver a lesser jolt, ranging from 10 to 35 volts.

The habitat of one type of numbfish — the bullseye electric ray — overlaps with the Pacific electric ray, but you’re more likely to spot the bullseye in the Sea of Cortez than Southern California. It’s easy to spot if you do come across one, thanks to the noticeable eyespot marking it has at the center of its body.

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