I know someone must have told you every animal needs blood to survive. Yes, to some people, every creature can only exist if blood circulates throughout their body. But that’s not generally true; there are animals with no blood in them.
Does this sound like a surprise? Here’s a list of animals without blood:
1. Spiders
Spiders do not have the common circulatory system; rather, they use hydraulic mechanisms to move around. Despite not having blood circulation, they can perform vital functions efficiently like hunting and building webs.
2. Jellyfish
Jellyfish live in the ocean. They have an incredible body design that allows for easy digestion of nutrients. They have no heart, blood or bone. But their nerves can detect temperature and touch. The interesting thing is that Jellyfish actually don’t hunt for food; instead, they await prey to come in contact with them.
3. Flatworms
Flatworms can be found in marine environments and freshwater. They do not have a circulatory system but rather a body that enables the diffusion of nutrients into the cells. This is how they get oxygen for breathing. Their soft and flat body also contributes to easy diffusion to the skin before entering the body. Flatworms do not have hearts, blood vessels or lungs.
4. Nematodes
Nematodes have a versatile body with no blood. They are microscopic worms that belong to the Phylum Nematoda which are often referred to as pinworms, roundworms, hookworms and whipworms. Their fluid helps in circulating nutrients for the body.
5. Sea Cucumber
Sea cucumber is a cucumber-shaped marine animal that dwells in the deep ocean. They have a body system that enables distribution of oxygen and nutrients throughout their body. Sea cucumbers have toxic internal organs that can harm predators.
6. Tardigrades
Tardigrades also known as water bears have a short body with four fused segments. They are quite resilient and not affected by high temperatures. When the environment is not favourable, “tun” is a system that helps them stay alive without a circulatory system.
7. Sea Anemones
Sea anemones belong to the same animal family as jellyfish and corals called Phylum Cnidaria. Despite not having a visible sense organ, sea anemones can distinguish what is edible from what is not. Their tentacles are a protection against predators. Moving inside water allows nutrients and oxygen into their body without a circulatory system.
8. Sea Stars
Sea stars, also known as starfish, usually live in shallow water. They have no brain or blood. They use water to pump nutrients into their body. Starfish are very adaptive in nature which contributes to their success as marine predators.
