Some sea creatures live in the deepest part of the ocean, beyond 200 metres beneath the sunlit surface waters. In such pitch-black depths, producing their own light can be very advantageous, such as for attracting prey or distracting predators. Here are 3 deep sea creatures which can do just that.
Deep Sea Anglerfish
The female Deep Sea Anglerfish (Melanocetus johnsoni) is one of the most bizarre-looking sea creatures. It gets its name from the elongated dorsal spine with a light-producing organ at the end, also known as a photophore. Using this photophore like a fishing lure, the fish waves it back and forth to attract prey. When the unsuspecting prey gets close enough, it will snap it up with its powerful jaws.
Here’s another fun fact about this inhabitant of the deep: Anglerfish mate for life – but in a rather grisly way. The male Anglerfish is tiny compared to the female, and its only way to survive is to find a mate. When it does, it bites into her skin and permanently fuses his face to her body so that their circulatory systems merge. From then on, she provides him with sustenance while he provides her with sperm. Check out this rare footage of a pair of Deep Sea Anglerfish mating:
The Firefly Squid (Watasenia scintillans) is also called the sparkling enope squid. Its mantle, head, arms and tentacles are dotted with tiny, light-producing photophores.
It lights up its body for two main reasons: to attract prey such as small fish or to attract a mate. And instead of ink, the Firefly Squid ejects clouds of luminescent mucus. This startles and distracts predators long enough for it to escape.
Every spring in Toyama Bay, Japan, Firefly Squids (or hotaruika in Japanese) come together for their annual mating season, resulting in a stunning electric-blue display.
The Black Dragonfish (Idiacanthus atlanticus) is a long, slender fish which lives at depths of about 2,000 metres.
Like many deep sea fish, the Black Dragonfish can produce its own light. It has photophores along its lower and upper surfaces, under its eyes and at the tip of its long barbel which acts like a fishing lure, flickering on and off to attract prey. When disturbed or threatened, its entire body lights up, even down the lengths of its fins.
What’s interesting is that the light it produces is in the blue/green range and also the red/infrared range (invisible to most animals including humans). This gives the species an enormous advantage, allowing it to find its way to unsuspecting prey through the deep dark depths of the ocean.
Here’s a video showing the Black Dragonfish’s photophores in action: