Scientists studying sharks off the coast of New Zealand have discovered that three deep-sea species glow in the dark.
One of the sharks is so big it is now the largest-known luminous vertebrate.
Bioluminescence is the technical name for a animal that glows in the dark. It is a chemical reaction that is widespread among marine life. However, it is the first time it has been documented in kitefin shark, the blackbelly lanternshark, and the southern lanternshark.
The sharks were collected during a fish survey off the east coast of New Zealand in January 2020.
All of the the sharks live in what is known as the mesopelagic or “twilight” zone of the ocean. This is between 200 and 1,000 metres deep, beyond which sunlight does not penetrate.
Researchers suggest the glowing underbellies may help camouflage them from any threats that might strike from beneath.