5 animals that do not have a brain

We often assume all animals have a brain just like us, but did you know that there are some creatures on Earth that don't have a brain at all? 

It might sound strange, but these animals have evolved in such a way that they don’t need a brain to survive. Instead, they rely on other systems within their bodies to perform basic functions like moving, eating, and reacting to their environment.

1. Jellyfish

Jellyfish are one of the most well-known animals that don’t have a brain. Instead of a brain, jellyfish have a simple nerve net. This network of nerves allows them to sense their environment and respond to things like light, temperature, and touch. Even without a brain, jellyfish can swim, capture food, and protect themselves from danger. Some species of jellyfish have existed for over 500 million years, proving that this animal doesn’t always need a brain to survive in the ocean.

2. Sea sponge

Sea sponges don’t have a brain, heart, or even a nervous system. So how do they survive? Sponges filter water through their bodies, capturing tiny particles of food like plankton.

They rely on the flow of water to bring nutrients to them and carry waste away. While they may seem more like plants than animals, sea sponges are indeed living creatures and have been around for over 600 million years.

3. Corals

Corals may look like colourful rocks, but they are actually tiny animals called polyps. Corals form large colonies that create the beautiful reefs we see in the ocean. Like sea sponges, corals don’t have a brain, heart, or a true nervous system. Instead, they rely on simple nerve cells to respond to their environment. Corals get most of their energy from tiny algae that live inside them, helping them survive and grow in their underwater homes.

4. Sea star (starfish)

Sea stars, also known as starfish, don’t have a brain, but they do have a nerve ring that controls their movements. This ring connects to the sea star’s arms, allowing it to move around and capture food. Sea stars can regenerate lost arms, which is another incredible feature. Even without a brain, sea stars are able to hunt, eat, and react to their surroundings.

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5. Portuguese Man O’ War

The Portuguese Man O’ War may look like a jellyfish, but it is actually a colony of different organisms working together. These organisms, called polyps, each have a specific job, such as capturing food or defending the colony. The Portuguese Man O’ War doesn’t have a brain, but its polyps work together to perform all the functions needed for survival. With its long, stinging tentacles, this creature is able to capture prey and defend itself without needing a central nervous system.

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This content was created with the help of an AI model and verified by the writer.