Sea Anemone & Hermit Crab - VideoIf You'll Be My Bodyguard, I Can Be Your Best Friend

Some sea anemones and hermit crabs establish a lifetime relationship where both animals gain a benefit. This type of symbiotic relations is referred to as mutualism.

The sea anemone attached to the hermit crab’s shell acts as the crab's bodyguard. In times of danger, the sea anemone may even entirely cover the crab with its tentacles and stinging threads to protect it. Most predators wouldn't dare attack this strong defence. The crab, in turn, provides the sea anemone with scraps of food from its leftover meals and also provides the anemone mobility by moving it from place to place. By riding on the hermit crab’s back the sea anemone has a better chance of catching plankton and other creatures that may pass by its tentacles.

This relationship can be so strong that sometimes young hermit crabs will seek out a young sea anemone an intentionally attach it to its shell where they may become partners for life. As the hermit crab grows older and grows out of its old shell, it detaches the sea anemone from its old shell and reattaches it to its new shell. They are partners for life.

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