Scientists discovered a pink sea anemone that builds protective shells for crabs

Pink sea anemone that builds homes for hermit crabs (Image: Kumamoto University)

A newly discovered pink sea anemone builds homes for hermit crabs. Paracalliactis tsukisome creates protective shell structures. The partnership between pink sea anemone and hermit crabs reveals surprising animal behaviour. Scientists believe it reshapes understanding of life in dark oceans.

Discovery in the Deep

Scientists discovered a pale-pink sea anemone off Japan’s coast. The species is named Paracalliactis tsukisome after Japanese poetic dye. It inhabits depths between 190 and 500 metres in darkness. The anemone forms a unique symbiotic relationship with hermit crabs.

Homes Made, Not Found

Unlike typical crabs, the anemone builds a protective carcinoecium. This hardened structure extends the crab’s shell safely and efficiently. Crabs no longer need to find empty snail shells nearby. The anemone anchors near the shell opening for optimal growth.

Mutual Benefits Underwater

The crab gains a stronger home, allowing larger body growth. The anemone benefits by gaining food from crab activity nearby. Stable-isotope analysis shows it feeds on particles and crab waste. Both species thrive better together than when living alone independently.

Science Reveals Surprising Behaviour

Micro-CT scans highlighted the unusual one-direction growth of the carcinoecium.The finding confirms that building complex building behaviours can be evolved by soft bodied animals.

This anemone was identified as a previously unknown species and genetic analyses proved that this species is not a hybrid. This collaboration poses new questions concerning the evolution of the deep-sea.

Implications to Marine Biology

This discovery brings out the underestimated complexity of deep-ocean ecosystems. It demonstrates that even very simple marine life can develop some cooperative behaviours. The partnership between animals can help researchers to know more about their survival strategies.