New Sex Tape Shows Never-Before-Seen Deep-Sea Anglerfish

Astounding, rare footage released Thursday gives new meaning to the concept of a “parasitic” relationships. Taped at 800 meters below the surface off the coast of the São Jorge Islands, the video captures the slow drifting courtship between two Fanfin Seadevil anglerfish. This David Attenborough-friendly sex tape is the first video of deepsea anglerfish mating and marks the first time males of this species have been observed.

And if you don’t look carefully, you might just miss him. Male Fanfin Seadevils, 60 times smaller than their female counterparts, are literal “sexual parasites” — equipped with large eyes and huge nostrils, these guys spend their days sniffing around the ocean depths for chemical attractants emitted by females. These big ladies, about a half a million times as heavy as the males, have the infamous bioluminescent “angler” at the tip of their snout and slowly move through the waters with whisker-like fin-rays. If, by chance, they encounter and get frisky — and “frisky” here is relative — you get a strange moment like this one, captured by researchers at the Rebikoff Foundation:

Like a clump of lint stuck to a Coachella raver, the small, male anglerfish hangs from the female’s belly while she slowly rolls through the ocean, surrounded by her bioluminescent pinpoints of light. This kind of attachment is unlike any position in mammal copulation: The male attaches by biting into the female’s body, causing the pair’s tissues and circulatory systems to fuse. He will hang here for the rest of his life, receiving nutrients through her blood while fertilizing her eggs. They become a single functioning organism as he completes his one purpose in life: to deliver sperm to a female.

“This is a unique and never-before-seen thing,” explained University of Washington professor emeritus Ted Pietsch, Ph.D. in a statement released Thursday. Pietsch wasn’t involved in capturing the footage but is considered the world’s expert on anglerfishes.

“It’s so wonderful to have a clear window on something only imagined before this.”

The video is also a unique opportunity to observe the body structure and behavior of the female Fanfin Seadevil. While there are more than 200 species of anglerfish, only 14 females of this species have been studied, each of which are stored in jars of alcohol in collections. Anglerfishes can’t live in laboratory conditions, and most die when brought to the surface because of changes in pressure and temperature. Footage like this is a game-changer for researchers, allowing them to be studied in their natural form.

Her form, in turn, is spectacular. Unlike other fish whose rays are connected by membranes and move as a single unit, the fins of the Fanfin Seadevil each have its own set of muscles that move independently. Scientists don’t know the purpose of these swirling, whisker-like fins but hypothesize they act like a network of sensory antennae that monitors for the presence of predators and prey. Meanwhile, pinpoints of bioluminescent light scatter across the fins and accumulate at her lure, like an Avatar wet dream.

As a nonprofit organization for marine science, this video is part of a larger effort by the Reibkoff-Niggeler Foundation to observe and document deep-water creatures using manned submersibles. They are particularly interested in documented deep-water squid species — but capturing never-before-seen footage of anglerfish hooking up isn’t so shabby either.