Researchers have photographed a large bioluminescent shark in deep water off New Zealand. The kitefin shark was a known species of ocean predator but was only recently discovered to be able to glow in the darkness of its deep-ocean environment. The kitefin shark, which can grow to 180cm, is now the largest-known luminous vertebrate in the world, on land or sea.

The researchers also identified two smaller species of shark — the blackbelly lanternshark, and the southern lanternshark that are also bioluminescent.

The Guardian reports that these sharks all live in what is known as the mesopelagic or “twilight” zone of the ocean, between 200 and 1,000 meters deep, beyond which sunlight does not penetrate. Seen from below, the sharks appear backlit against the bright surface of the water, leaving them exposed to potential predators without any place to hide.

Researchers suggest these three species’ glowing underbellies may help camouflage them from any threats that might strike from beneath.

In the case of the kitefin shark, which has few or no predators, it is possible that the slow-moving species uses its natural glow to illuminate the ocean floor while it searches for food, or to disguise itself while approaching its prey.

Scientists have taken the first-ever picture of a glow-in-the-dark shark

Thanks to Joan Druett for contributing to this post.