Glow in the Dark Deep-Sea Species
The phenomenon of bioluminescence

The kitefin shark is now the biggest-known luminous vertebrate and inhabits the deep sea. PC: Dr. J. Mallefet - FNRS, UCLouvain

Comb-jelly luminescence isn't fully understood. It's thought to be defensive, but we don't know for sure. PC: Steve Haddock/Monterey Bay Aquarium Research Institute.

The Abraliopsis Squid uses illumination to blend in with the sky. PC: Steve Haddock/Monterey Bay Aquarium Research Institute.
