This squid can give up a piece of arm that keeps shining

Octopoteuthis deletron carries eight arms into adulthood: the two long food tentacles present in the young are absorbed during development. This squid thus resembles, by its number of appendages, an octopus, while remaining a squid.

The extremities of his arms have luminous organs. To study its defense, the researchers attached a soft brush to the arm of an underwater robot. They found that the animal could abandon fragments of appendages whose spikes continued to flash and stir.

The detached piece serves as a diversion while the rest of the animal escapes the threat. The robots have also documented color changes and complex patterns, the full meaning of which remains to be deciphered. The light of his arms is therefore not a simple ornament: it can become a signal separate from its owner.