Not all animals have brains, and they are all sea creatures. You are probably asking yourself how to survive without a brain? Well, let’s find out. From the war man to the sea cucumber, here are 12 animals that don’t have a brain and a quick look at how the hell they survive!
What’s in the brain?
The brain is essentially a group of grouped neurons. Animals (including humans) filled with these nerve cells control all body functions.
Brainless creatures are usually very simple animals. They use basic biological characteristics to survive. Many of them are immobile and use sensory nerves to “find” food and avoid danger.
Curiously, it looks like technology. Many of our devices (such as computers and smartphones) do not have brains, but use sensors to detect light, movement, chemicals, etc. Brainless animals act in the same way, allowing them to do what they need to survive.
# 12 Animals without a brain: sea urchins
Sea urchins are pointy, spiky animals, and any barefoot beach goer can find it in the worst way. Fortunately, outside of South Florida, sea urchins are not poisonous.
The creature has an innumerable number of legs and controls nutrition through its aquatic vascular system. This system changes the amount of pressure and water in his body, allowing him to move faster. (The starfish works the same way.)
The creature’s mouth is underneath. They expel excrement from the upper part of their body. The sea urchin sits on rocks, scraping and feeding on algae. In many ways, this action keeps the ocean clean.
# 11 Animals Without Brains: Sea Cucumbers
The worm-like sea cucumber feeds on plankton, and leathery animals are found everywhere. Sea cucumbers are extremely dangerous, but without a brain, they don’t necessarily pose a deliberate threat. They are capable of releasing a toxic substance called holothurin, which can blind people forever.
There are over a thousand types of sea cucumbers. Many of the species are found in deep water. They can swim up to 3,300 feet, returning to the ocean floor.
Sea cucumbers feed instinctively, using the tubular legs around their mouth to catch and eat food. Their diet consists of aquatic invertebrates, algae, and waste. Curiously, although they have no way of even realizing it, these sea creatures exhibit asexual and sexual reproduction.
# 10 Animals without a brain: jellyfish
This family of translucent creatures, called “jelly”, is unique. All other creatures without a brain are usually immobile, often spending their entire existence in one place. Jellyfish move with the ocean current. They also spray with water, which can propel them forward.
Jellyfish functions through a network of sensory nerves. The tentacles react to foreign objects with a shooting bite. This bite releases a toxin that can neutralize or kill the intruder.
# 9 Animals Without Brains: Corals
Corals and jellyfish belong to the cnidarians family. Their bodies are asymmetrical and they both sting their enemies. Classified as a plant, coral is actually a living animal without a brain.
Here is the big difference between plants and animals: animals seek food; the plant produces its own. Coral joins the animal in search of food. They make up small parties of tiny creatures. These coral polyps feed on zooplankton in the ocean. Corals catch plankton with their retractable tentacles and then feed.
# 8 Animals Without Brains: Starfish
The starfish is the cousin of the sea urchin. But – wait! is not a fish. In fact, this species cannot swim. Starfish spend all their time at the bottom of the ocean. While you may find them floating or beached, it is never by choice!
At the end of each hand, creatures have tiny eyes that they use to distinguish darkness from light. A starfish doesn’t need a brain. He uses basic sensors to keep track of enemies and food.
Starfish have five to 40 pointed arms. If the predator bites off a hand (or two), the animal can restore them.
# 7 Animals Without Brains: Shellfish
Molluscs are bivalve molluscs, which are molluscs with a compressed body inside a pair of hinged shells. Other members of the family include oysters, mussels, clams, and scallops. Molluscs can open and close their shells.
The mollusk manages to function thanks to its nervous system. They are popular in the fishing world as the shellfish are easy to catch and live all over the world.
Shellfish have kidneys, stomach, mouth, nervous system, and beating heart.
# 6 Animals Without Brains: Man-O-Wars
Another wobbly creature with a venomous sting, the Portuguese Man-War is on the list of the strangest animals on the planet.
Although we are talking about the creature in the singular, we should actually say man-o-wars. You see, the animal is actually a colony of polyps, also called zooids. Bound by tissue, the colony cannot survive individually.
This creature has a deadly bite, but is useless against its greatest enemy, the Sea Turtle. The sting of a warship cannot pierce the thick skin of a turtle. A sea turtle is not deterred even by a tongue bite. The fish also goes to the mat with the birds. War-man dives deep as birds approach and bubble gas.
# 5 Animals Without Brains: Sea Sponges
Among the most primitive animals of the animal kingdom, the sea sponge remains relatively motionless. It is the water that moves them and makes them look like they are dancing. Their survival is centered around filtration of detritus from the ocean. They have no brain, organs, neurons, or tissues.
What sea sponges have in common with humans is a genetic component that resembles synapses. Synapses use neurotransmitters to transmit messages across the synaptic gap.
Here’s another curious fact about this animal: when a foreign object enters their body, the creature draws in water and then jumps it out, sneezing violently. This is a recent scientific discovery, and it means that despite the lack of a brain, the sea sponge is aware of its ecosystem.
# 4 Animals Without Brains: Oysters
Compared to clam, oyster is notorious for containing precious pearls in its shell. But this is a treasure hunt, as your chances of finding the perfect pearl are roughly one in a million.
Oysters filter the water and remove organic particles such as plankton in order to eat them. They can filter up to 50 gallons of water a day, giving them enough food to last for a while.
# 3 Animals without a brain: sea lilies
Sea lilies resemble plants with feathery limbs. They sit motionless at the bottom of the ocean all their lives. There are also studies that show that the sea lily is able to swim to a new location when it can no longer find food. They can travel at speeds of up to 140 miles per hour if required.
The sea lily is associated with starfish, sea urchins, and sea cucumbers. The animal has a small mouth at the center of its body, and it feeds mainly on the excrement of animals that float to the bottom of the ocean. So, like some of the other animals on this list, the sea lily instinctively contributes to keeping the ocean clean.
Typically, sea lilies can reach 30 inches in length, although fossils indicate that they have grown to 80 feet.
# 2 Animals Without Brains: Sea Splash
Get ready for the weirdest creature on this list. Let’s start with the fact that sea squirt can be both male and female. As a hermaphrodite, he has both reproductive organs – this creature does not need an assistant to have children. Their tadpole larvae are the result of the sperm and eggs of a single animal.
Here’s where it gets weird: the sea-spray larva does have a brain; it’s tiny, but it’s there. However, the creature cannot find food or eat in the form of a larva, so it quickly settles in place and remains there for the rest of its life. As soon as the sea stream has found its “home”, it begins to eat its brain.
After disappearing, the creature spends the rest of its life without a brain!
# 1 Animals without a brain: sea anemones
The sea anemone is another plant-like animal. However, the sea anemone is very alive and seeks food, which it uses its long tentacles to catch and eat.
A unique feature of the sea anemone is its ability to change shape. This action is achieved by retracting and rotating the long muscles of the tentacles. It is amazing to see how they change shape and form, swaying in the water. This demonstrates how animals, despite lacking a brain, can use sensors to respond to their surroundings.
Next: 9 largest snails in the world