Boxer crabs and sea anemones form one of the most unusual and astounding symbiotic relationships in the entire animal kingdom. These crabs wield sea anemones attached to their claws in horizontal motions as they move. This colourful display serves as a natural deterrent to predators, and when directly threatened, the crab will utilize the sea anemone in a forward, ‘punching’ movement towards the aggressor. The sea anemone’s stinging tentacles serve as the ultimate defence mechanism for the crab
In exchange for this defence, boxer crabs feed their helpful partners. The crabs utilize the sea anemone’s tentacles to collect food particles then subsequently digest the debris and provide adequate meals in return, making for the most unlikely and amazing friends.
The crabs – unflatteringly classed as “kleptoparasites” – regulate the food intake and, hence, the growth of their anenomes. Scientists go so far as to liken this to the careful cultivation of bonsai.