A Match Made 4,000 Meters Under the Sea
Deep in the pitch-black abyss of the ocean, a light flickers in the darkness. It’s an angler fish, glowing to lure in unsuspecting prey. With its huge head, sharp teeth, and illuminated fishing rod protruding from its head, the angler fish looks like something out of a sci-fi movie. These scary-looking creatures live at depths of up to 4,000 meters, where life is scarce. So when two angler fish actually cross paths, they grab onto each other and never let go. Their bizarre mating ritual is unlike anything else in the animal kingdom.
Two Become One
When a tiny male angler encounters a female, he latches onto her with his sharp teeth. Then, in an act of complete biological devotion, the male physically fuses with the female until they are practically one organism. His mouth and body tissues melt into her skin, connecting their circulatory systems.
“The male is merely an appendage of the female and entirely dependent on her for nutrition,” writes fish expert Theodore Pietsch. He taps into her blood supply like a parasite, forever linked to his mate. One female can carry six or more males on her body. Talk about excessive baggage in a relationship!
Why Settle Down?
This extreme, permanent attachment likely evolved because of the this fish’s lonely lifestyle. In the dark, cold depths of the ocean, these fish can go months without seeing another living creature. So when a male finally tracks down a potential mate, he holds on with all his might.
Other deep-sea species reproduce through external fertilization, releasing eggs and sperm into the water and hoping they make contact. But for angler fish, that’s too risky. By permanently fusing to the female, the male has direct access to her eggs, ensuring his genes are passed on.
Immune System Sacrifice
Recent research reveals that the female angler fish makes an incredible sacrifice for her mate. She actually dismantles parts of her immune system to allow the male to fuse into her flesh. This species have lost the cells and antibodies that would normally attack foreign tissue.
Scientists think the females may have a backup immune response not yet discovered. Otherwise, they’d be susceptible to infections. Understanding how angler fish adapt their immune systems could provide insight for humans with autoimmune disorders.
Angler fish may have taken mate attachment to the extreme, but it seems to work. These alien-like creatures have thrived for millions of years in one of Earth’s most inhospitable environments. Their bizarre mating strategy is a testament to how far species will go to find love in the deep dark sea.