Anglerfish live beneath the deepest parts of the ocean, where it is dark, lonely, and thought to be an inhospitable habitat for animals. But that does not seem to bother the allegedly ugliest animal on the planet.

Male anglerfish are generally smaller than females and do not have the sharp teeth that female anglerfish have. It seems that it does not need that kind of adaptation as females grew to be a parasitic mate.

According to a Roaring Earth report, Kirsten and Joachim Jakobsen have captured a video in 2016 of a six-inch female anglerfish and her mate using the submersible operated by the Rebikoff-Niggeler Foundation. It was a never before seen footage of mating as the smaller male anglerfish is fused to the female's body.

The groundbreaking footage brings to light some fantastic facts about anglerfish. Scientists know very little about the mating process of anglerfish and have never seen a male one before.

Female vs. Male

The female anglerfish is a terrifying-looking marine animal that hunts in the deepest parts of the ocean. She uses her bioluminescent light to lure her prey and suddenly swallows it no matter the size, even if it was twice as big as it is.

On the other hand, the male anglerfish does not have similar characteristics as its female counterpart. Males do not have the females' killer instinct; it also does not have teeth and is very small. Male anglerfish never hunt or kill. It could not even defend itself against a goldfish if it were attacked.

Male anglerfish seems to be underdeveloped testicles with fins and other necessary sensory organs to detect light and smells. But its sole purpose in its existence is to find a female anglerfish to mate. It does not stop to eat n search for love, but it does not starve because it is born with a giant liver that can sustain the male anglerfish for many months.

Read Also: 16 Species of Ultra-Black Fish Goes Invisible in the Ocean's Dim Backdrop

Anglerfish Mating

According to David Clear, once the male anglerfish finds a female anglerfish, it bites into her belly, a horrific event begins. The tissues of the male start to melt as it slowly fuses with the female's body forever. His eyes, head, fins, and organs will all melt as it merges with her body and becoming a part of her living as a parasite forever.

Meanwhile, the female's blood vessels would begin to penetrate the male's body to establish a connection in which nutrients from her body will be flushed into the male to keep it alive so that its testicles will grow. In that sense, the male becomes a permanent sperm factory for the female anglerfish.

The anglerfish can now reproduce by squirting some sperm and eggs into the open water after having both the male and female reproductive organs. This cruel lifecycle ensures that the species continue unto the next generations. However, one pair of testicles is sometimes not enough, so females would absorb eight more males.

Sexual Parasitism

The relationship between male and female anglerfish is just one example of sexual parasitism common in 20 animal species.

Those who engage in sexual parasitism usually present extreme dimorphism wherein the females are much bigger than the males; to be exact, females could be 60 times bigger than the males and half a million times heavier.

The only option for males is to fuse itself with the female and live as a parasite, thus the term sexual parasitism.

Read More: Oral Contraceptives Pollute Water Which Hinders the Ability of Fish to Reproduce

Check out more news and information on Fish on Science Times.