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Bobtail Squid Shimmers

A shimmering bobtail squid.
Chris Frazee and Margaret McFall-Ngai via Wikimedia

Within hours of birth, the Hawaiian bobtail squid attracts bioluminescent bacteria, which colonize a special light organ above its eyes. The bacteria and squid are able to live independently, but they both benefit from this relationship: The bacterial light helps the squid avoid predation, and the bacteria gain a safe home and consistent nutrients.