This long-limbed, golden-locked creature should surely be brachiating its way through the canopy of the Sumatran jungle. But this is an orangutan in name only. It’s an orangutan crab, an inhabitant of the coral reefs of the Indo-Pacific. It is commonly found in association with another enigmatic species, the bubble coral, which inflates its grape-like polyps during the day.

This exposes a greater surface area to the sun’s rays to nourish the symbiotic algae that live within its tissues. It extends its stinging tentacles to feed at night. The crab-coral relationship may be symbiotic, too, or perhaps the crab just steals food ensnared by its host – no one really knows for sure.