Animal names can be inspired by a wide range of things. Some are named after the place where they live, like the deep-sea catshark Apristurus spongiceps, who resides (unsurprisingly) in the deep sea. Others are named after a distinctive physical feature, like the red-lipped batfish Ogcocephalus darwini, who has vibrant red “lips”. Some are even named after famous people, like the Kate Winslet beetle Agra katewinsletae, who was discovered by a fan of the movie Titanic.

Today, we are looking at ocean animals who are inspired by … other animals! Read on to learn about five critters named after fellow members of the animal kingdom.

Dogfish

It’s a shark, not a dog.

Dogfish are a group of small sharks in the family Squalidae. Most species reach about 1-3 feet in length, and all have two dorsal fins and no anal fin. Some dogfish have a spine along their dorsal fins, including the aptly-named spiny dogfish. The spiny dogfish also has venom glands at the base of its spine, which can cause a nasty sting. In fact, Divers Alert Network reports that dogfish were mentioned in a fishing poem from 200 AD: “These in punctures sharp, a fatal poison from their spines inject.”

Dogfish get their name from their pack-like behavior: they can sometimes be seen feeding in large groups of hundreds or more.

Frogfish

It’s a fish, not a frog.

Frogfish are any members of the family Antennariidae, a type of anglerfish that includes about 50 species. They’re found in shallow tropical and subtropical ocean waters around the world and are fairly small—the biggest species only grows to 12 inches (30 cm) long. They have modified pectoral fins that resemble legs, which allow them to “walk” along the ocean floor looking for prey.

These “legs” are where the frogfish gets its name! They have a bend in the limb that resembles an elbow, which looks rather similar to the forelegs of a frog. The resemblance is even greater when the frogfish walks by alternating their two front fins.

Sea butterfly

It’s a snail, not a butterfly.

Sea butterflies (also known as pteropods) are small invertebrates in the phylum Mollusca. Most are pretty tiny, less than one centimeter long, so they can be difficult to spot in the open ocean. Many species have shells which dissolve in acidic conditions, and scientists are studying pteropods to understand the effects of ocean acidification.

If you look closely at the sea butterfly, you’ll see two translucent flaps that look like wings. These allow the sea butterfly to swim, but are also what gives them their name! The wings are similar to the thin, branching wings of a butterfly.

Seahorse

It’s a fish, not a horse.

Seahorses are a group of 47 species in the genus Hippocampus and are closely related to pipefishes and seadragons. They are generally pretty small, and range from about the size of a thumbnail to more than a foot long. Almost 1/3 of the seahorse species we know of were discovered within the last decade—which means there are likely more that haven’t been discovered yet.

The name Hippocampus comes from the Greek word hippokampos, which was a mythological sea monster with the body of a horse and the tail of a fish. Although a tiny seahorse might not be the massive sea monster of lore, it does fit the anatomical description.

Whale shark

It’s a shark, not a whale.

Whale sharks are not to be confused with whales, which are mammals—sharks are fish! But both whales and whale sharks dominate our ocean with their size. Whale sharks are the biggest fish in the world and can grow up to 40 feet long and weigh up to 20,000 pounds. That’s as heavy as a garbage truck!

It’s not a surprise that this size similarity is what gives whale sharks their name. But they have another thing in common with whales: unlike many sharks who hunt and bite their prey, whale sharks filter feed. They swim through the water with their mouths open and suck out plankton suspended in the water—similar to filter feeding whales.