10 Animals That Don’t Have a Brain

Sea Urchins

Sea urchins are pointy, spiky animals, and any beachcomber in their bare feet might discover this in the worst way. Fortunately, outside of South Florida, sea urchins are not poisonous. The creature has an untold number of legs and controls feeding with its water vascular system. That system changes the amount of pressure and water in its body, allowing it to move faster. (The starfish operates the same way.)  The creature’s mouth is beneath it. They expel excrement from the top of their bodies. The sea urchin sits on stones, scraping and feeding on algae. In many ways, this action keeps the ocean clean.

Sea Cucumbers

Even without a brain, sea cucumbers are capable of blinding humans. The wormlike sea cucumber feeds on plankton, and the leathery-skinned animals are everywhere. Sea cucumbers are extremely dangerous but, without a brain, they’re not necessarily a deliberate threat. They are capable of releasing a toxic substance called holothurian, which can blind humans permanently. There are more than a thousand types of sea cucumbers. Many of the species live in deep water. They can swim up to 3,300 feet, floating back to the bottom of the ocean floor.

Jellyfish

Called “jellies,” this family of translucent creatures is unique. All other creatures without brains tend to be immobile, often spending their entire existence in a single spot. Jellyfish move with the ocean current. They also squirt water that can move them forward. The jellyfish functions through a network of sensory nerves. Tentacles react to foreign objects with a shooting sting. That sting releases a toxin capable of neutralizing or killing the intruder.

Corals

The coral and jellyfish are part of the Cnidarians family. Their bodies are asymmetric and they both sting their enemies. Categorized as plants, coral is actually a living animal without a brain. Here’s the great distinction between plants and animals: animals seek food; the plant produces its own. The coral joins the animal in seeking food. They make up small lots of tiny creatures.

Star Fish

The starfish is a cousin of the sea urchin. But — wait for it! — it’s not a fish. The truth is this species can’t swim. Starfish spend all their time at the bottom of the ocean. Though you can find them floating or washed ashore, that’s never by choice! At the end of each arm, the creatures have tiny eyes that they use to distinguish dark from light. The starfish has no use for a brain. It uses basic sensors to stay alert for enemies and food. Starfish have five to 40 spiky arms. If a predator should bite off an arm (or two), the animal can regenerate them.

Clams

Clams are bivalves, which is a mollusk with a compressed body inside of a pair of hinged shells. Others in the family include oysters, mussels, clams, and scallops. Clams can open and close their shells. The clam manages to function thanks to its nervous system. They’re popular in the fishing world as clams are easy to catch and live all over the world. Clams have kidneys, a stomach, mouth, nervous system, and a beating heart.

Man-O-War

Another wobbly-like critter with a venomous sting, the Portuguese man-o-war is up there on the list of strangest animals on the planet. While we refer to the creature in the singular, we should actually say “man-o-wars.” You see, the animal is actually a colony of polyps, also referred to as zooids. Connected by tissue, the colony cannot survive individually. The creature has a deadly sting, but that’s useless against its greatest foe, the Sea Turtle.

Man-O-War

Another wobbly-like critter with a venomous sting, the Portuguese man-o-war is up there on the list of strangest animals on the planet. While we refer to the creature in the singular, we should actually say “man-o-wars.” You see, the animal is actually a colony of polyps, also referred to as zooids. Connected by tissue, the colony cannot survive individually. The creature has a deadly sting, but that’s useless against its greatest foe, the Sea Turtle.

Oysters

Relative to the clam, the oyster is infamous for enclosing precious pearls in its shell. But it’s a treasure hunt since your odds of finding a perfect pearl are roughly one in a million. Oysters filter water and remove organic particles — like plankton — to eat them. They can filter up to 50 gallons of water per day, giving them enough food to lasts a while.

Sea Anemones

Relative to the clam, the oyster is infamous for enclosing precious pearls in its shell. But it’s a treasure hunt since your odds of finding a perfect pearl are roughly one in a million. Oysters filter water and remove organic particles — like plankton — to eat them. They can filter up to 50 gallons of water per day, giving them enough food to lasts a while.