Examples of Commensalism in Nature

Commensalism in Nature

Animals often form special relationships called symbiosis. In some of these partnerships, both animals help each other. But in commensalism, only one animal gets something good, while the other is not helped or hurt. It’s like sitting next to someone eating popcorn and catching the pieces that fall—you get a snack, and they don’t even notice!

One famous example is the remora fish and the shark. Remoras have suction disks that let them attach to sharks. The remora gets a free ride and eats leftover food from the shark’s meals. The shark doesn’t seem to notice or care—it isn’t helped or harmed.

Another example is birds that build nests in trees. The birds get a safe home high off the ground. The tree doesn’t get anything from the birds, but it’s not harmed either.

Barnacles are tiny sea animals that stick to whales. The barnacles travel to food-rich waters on the whale’s back. The whale just carries them along and is not affected.

Cattle egrets are birds that follow cows in fields. When cows walk, they stir up insects. The egrets eat these insects, but the cows don’t notice the birds at all. In each of these cases, one animal is the host or "ride," while the other animal is the hitchhiker that gets the benefit.

Commensalism is different from mutualism, where both animals benefit, and parasitism, where one animal is harmed. Scientists study these relationships to learn how animals interact and help keep nature in balance.

Interesting Fact: Some scientists use cameras and tracking devices to find out how hitchhiker animals travel and survive with their hosts.