This image shows a baby Hawaiian bobtail squid, measuring just 1.5 cm across.
Native to the Pacific Ocean, Hawaiian bobtail squid are nocturnal predators that remain buried under the sand during the day and come out to hunt for shrimp near coral reefs at night. The squid have a light organ on their underside that houses a colony of glowing bacteria called Vibrio fischeri. The squid provide food and shelter for these bacteria in return for their bioluminescence.
The light organ is attached to an ink sac, which they use like a type of shutter, controlling the amount of light released. The squid matches the light the bacteria produce to the moonlight and starlight, masking its silhouette and making it invisible to predators swimming below. This type of camouflage is called counter-illumination. The black ink sac and light organ in the centre of the squid’s mantle cavity are clearly seen.
This image was submitted to the 2017 Wellcome Image Awards and was taken by Mark R Smith of Macroscopic Solutions.