Wild animals need one other to survive. Sometimes they help one other. Other times, they fight. All these relationships are known as symbiosis. There are five main types of symbiosis. Here is how they work.




Imagine you are diving deep in the Pacific Ocean. You will probably see clownfish with bright colors swimming near the bottom. You might also find sea anemones. The relationship between clownfish and sea anemones is called mutualism. This is when two animals help each other out. 


Sea anemones have tentacles that sting. When a small animal touches an anemone, the tentacle releases poison. This stuns the small animal. It allows the anemone to bring the animal to its mouth and eat it. Clownfish are safe, though. They have a mucus on their bodies. It stops the tentacles from stinging. So, the clownfish swim comfortably between the anemones.


Other fish want to eat the clownfish. When they see food, the bigger fish come down for a quick meal. These fish are not safe from the anemones, though. They get caught and eaten instead! This way, the anemones get their food. It works out for the clownfish too. The anemones keep them safe.



In commensalism, one animal lives with or inside another animal. The other animal is called the host. In commensalism, animals do not help their host. They do not hurt it either.


One example is barnacles and whales. Barnacles are sea animals with shells. They attach themselves to the skin of whales. This does not seem to bother the whales. The huge whales take the tiny barnacles to areas where there is food. There, they both get to eat tiny animals called plankton.



If you keep swimming in the ocean, you won't just find peaceful relationships. Animals often hurt each other, too. Predation is when predators hunt and kill prey. The orca, or killer whale, is an ocean predator. Orcas hunt and eat many other animals. They are not hunted by any other predator, though. They are at the top of the food chain.  




Another harmful relationship is parasitism. This happens when one animal lives with or inside a host animal. This time, the host does get hurt. The animal hurting it is called a parasite. 


Barnacles do not hurt whales. They can be parasites for other animals, though. They can go inside swimming crabs. The crabs don't die, but they get hurt.




Competition is when animals fight over food or space. It can happen between animals of the same type, or species. This is called intraspecific competition. It also happens between different species. This is called interspecific competition.


Coral and sponges are an example of competition. Coral are sea creatures with tentacles. They use calcium to make hard coral reefs. Many animals live on coral reefs.


Sponges are sea creatures that live on coral reefs. If sponges eat too much, the coral will not have enough food. If too many coral die, the reef ends up disappearing. This is also bad for the sponges. They cannot live without a reef.


Humans can hurt the environment too. For example, pollution changes how animals live. That is why humans need to be careful with the environment.


Symbiosis: The Art of Living Together

The symbiotic relationship between an anemone (Heteractis magnifica) and a clownfish (Amphiron ocellaris) is a classic example of two organisms benefiting the other; the anemone provides the clownfish with protection and shelter, while the clownfish provides the anemone nutrients in the form of waste while also scaring off potential predator fish.

apex predator

species at the top of the food chain, with no predators of its own. Also called an alpha predator or top predator.


relationship between organisms where one organism benefits from the association while not harming the other.


contest between organisms for resources, recognition, or group or social status.

coral reef

rocky ocean features made up of millions of coral skeletons.


relationship between organisms of different species, in which both organisms benefit from the association.


behavior of one animal feeding on another.

sea anemone

type of marine animal related to corals and jellies.


simple type of marine animal permanently attached to something in the water.


two or more distinct organisms living together for the benefit of one or both.


associating with another organism, not always to the mutual benefit of either species.


poisonous substance, usually one produced by a living organism.