“It’s not over yet.” Filmmakers deployed a robot crab into the sea. How the other crabs reacted was extraordinary

For the BBC TV series Spy in the Ocean, filmmakers had a unique solution to getting amongst the action: sending in ‘spy cameras’.

Animatronic robots, with a built-in camera, were sent to film incredible behaviour that would likely have been disrupted by human presence.

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And in Australia, a spider crab spy cam captured hordes of spider crabs outgrowing their tough shells. While their new shell is larger, it is softer and takes time to harden – and the soft shells makes them vulnerable to hunting stingrays.

To protect the softer-shelled crabs, the harder-shelled crabs build ‘towers’ in the ocean to cover them. One of the crabs even uses the spy cam to hide from the stingray.

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But when the imposter is attacked by the stingray, the spider crabs do something incredible.