Deepest-Living Predator Evolved Ingenious Strategy for Having Sex

Small dating pool? Make do with what you've got.

Lizardfish hermaphrodite reproduction

What do you do when you live 8,000 feet deep in the ocean, where it’s dark, lonely, and probably pretty boring, but you really want to get it on? You get creative and learn to copulate with any member of your species that comes your way.

That’s exactly what the deepsea lizardfish, or Bathysaurus ferox, has done, evolving a reproductive mechanism that’s unusual in predatory fish. The fish regained notoriety for its horrifying looks when a group of Australian researchers recovered samples and posted photographs in early June.

What’s more interesting than its looks, however, is the way it reproduces. Say you’re a male deepsea lizardfish looking to father some kids. At 3,280 feet to 8,200 feet below the surface of the water, the dating pool is small, and it doesn’t help that your surroundings are so dark and sparse. How do you maximize your chances of scoring with the next lizardfish that comes along?

deepsea lizard fish terrifying predator
They say if you stare directly into the Basilisk's eyes you'll turn to stone.

Evolution’s solution: Develop hermaphroditism, which means that any individual fish has both male and female sex organs (testicular and ovarian tissues) within its body, allowing it to reproduce with any other member of its species that it might encounter on the lonely ocean floor. It’s an effective evolutionary strategy — and a surprisingly common one among many animals and higher plants.

The deepsea lizardfish has evolved to be equally creative with its other survival strategies, gaining the ability to eat just about everything in sight. It hunts, in a similar fashion to other seafloor-dwelling fish, by burying itself in sand or mud and then lying in wait for hapless victims to come swimming by. Once that happens, it grabs them with its hooked teeth, ensuring that struggling only quickens its prey’s demise.

deepsea lizard fish hunting seafloor
Hello, beautiful.

Given its terrifying looks and cut-throat hunting abilities, one might hope that the deepsea lizardfish would have at least one weakness. What that might be remains unclear, but we do know that its ability to hook up isn’t it. Even small populations can’t slow these fish down, since there are no restrictions on how, when, and with whom they produce offspring. With that evolutionary trait in their back pocket, as just one of a number of characteristics that work together, the deepsea lizardfish will likely continue its horrifying reign as a top predator of the deep ocean for some time to come.

Baby deepsea lizardfish jaws
Even the babies look like tiny alien alligator heads.