The Horrors of Anglerfish Mating

Masaki Miya et al. "Evolutionary history of anglerfishes (Teleostei: Lophiiformes): a mitogenomic perspective," BMC Evolutionary Biology 10, article number: 58 (2010), Wikimedia Commons // CC BY 2.0
Masaki Miya et al. "Evolutionary history of anglerfishes (Teleostei: Lophiiformes): a mitogenomic perspective," BMC Evolutionary Biology 10, article number: 58 (2010), Wikimedia Commons // CC BY 2.0

When you think of an anglerfish, you probably think of something like the creature above: Big mouth. Gnarly teeth. Lure bobbing from its head. Endless nightmares. 

During the 19th century, when scientists began to discover, describe, and classify anglerfish from a particular branch of the anglerfish family tree—the suborder Ceratioidei—that’s what they thought of, too. The problem was that they were only seeing half the picture. The specimens that they were working with were all female, and they had no idea where the males were or what they looked like. Researchers sometimes found some other fish that seemed to be related based on their body structure, but they lacked the fearsome maw and lure typical of ceratioids and were much smaller—sometimes only as long as 6 or 7 millimeters—and got placed into separate taxonomic groups.

It wasn’t until the 1920s—almost a full century after the first ceratioid was entered into the scientific record—that things started to become a little clearer. In 1922, Icelandic biologist Bjarni Saemundsson discovered a female ceratioid with two of these smaller fish attached to her belly by their snouts. He assumed it was a mother and her babies, but was puzzled by the arrangement.

“I can form no idea of how, or when, the larvae, or young, become attached to the mother. I cannot believe that the male fastens the egg to the female,” he wrote. “This remains a puzzle for some future researchers to solve.”

When Saemundsson kicked the problem down the road, it was Charles Tate Regan, working at the British Museum of Natural History in 1924, who picked it up. Regan also found a smaller fish attached to a female ceratioid. When he dissected it, he realized it wasn’t a different species or the female angler’s child. It was her mate.

The “missing” males had been there all along, just unrecognized and misclassified, and Regan and other scientists, like Norwegian zoologist Albert Eide Parr, soon figured out why the male ceratioids looked so different. They don’t need lures or big mouths and teeth because they don’t hunt, and they don’t hunt because they have the females. The ceratioid male, Regan wrote, is “merely an appendage of the female, and entirely dependent on her for nutrition.” In other words, a parasite.

When ceratioid males go looking for love, they follow a species-specific pheromone to a female, who will often aid their search further by flashing her bioluminescent lure. Once the male finds a suitable mate, he bites into her belly and latches on until his body fuses with hers. Their skin joins together, and so do their blood vessels, which allows the male to take all the nutrients he needs from his host/mate’s blood. The two fish essentially become one.

With his body attached to hers like this, the male doesn't have to trouble himself with things like seeing or swimming or eating like a normal fish. The body parts he doesn’t need anymore—eyes, fins, and some internal organs—atrophy, degenerate, and wither away, until he’s little more than a lump of flesh hanging from the female, taking food from her and providing sperm whenever she’s ready to spawn.

Extreme size differences between the sexes and parasitic mating aren’t found in all anglerfish. Throughout the other suborders, there are males that are free-swimming their whole lives, that can hunt on their own and that only attach to the females temporarily to reproduce before moving along. For deep-sea ceratioids that might only rarely bump into each other in the abyss, though, the weird mating ritual is a necessary adaptation to keep mates close at hand and ensure that there will always be more little anglerfish. And for us, it’s something to both marvel and cringe at, a reminder that the natural world is often as strange as any fiction we can imagine.

Naturalist William Beebe put it nicely in 1938, writing, “But to be driven by impelling odor headlong upon a mate so gigantic, in such immense and forbidding darkness, and willfully eat a hole in her soft side, to feel the gradually increasing transfusion of her blood through one’s veins, to lose everything that marked one as other than a worm, to become a brainless, senseless thing that was a fish—this is sheer fiction, beyond all belief unless we have seen the proof of it.”

Not-So-Fancy Feast: Your Cat Probably Would Eat Your Rotting Corpse

Tycson1/iStock via Getty Images
Tycson1/iStock via Getty Images

Cat enthusiasts often cite the warmth and companionship offered by their pet as reasons why they’re so enamored with them. Despite these and other positive attributes, cat lovers are often confronted with the spurious claim that, while their beloved furry pal might adore them when they’re alive, it won’t hesitate to devour their corpse if they should drop dead.

Though that’s often dismissed as negative cat propaganda spread by dog people, it turns out that it’s probably true. Fluffy might indeed feast on your flesh if you happened to expire.

A horrifying new case study published in the Journal of Forensic Sciences offers the fresh evidence. The paper, first reported by The Washington Post, documents how two cats reacted in the presence of a corpse at Colorado Mesa University’s Forensic Investigation Research Station, or body farm, where the deceased are used to further forensic science for criminal investigations.

The study’s authors did not orchestrate a meeting between cat and corpse. The finding happened by accident: Student and lead author Sara Garcia was scanning surveillance footage of the grounds when she noticed a pair of cats trespassing. The cats, she found, were interested in the flesh of two corpses; they gnawed on human tissue while it was still in the early stages of decomposition, stopping only when the bodies began leaching fluids.

The cats, which were putting away one corpse each, didn’t appear to have a taste for variety, as they both returned to the same corpse virtually every night. The two seemed to prefer the shoulder and arm over other body parts.

This visual evidence joins a litany of reports over the years from medical examiners, who have observed the damage left by both cats and dogs who were trapped in homes with deceased owners and proceeded to eat them. It’s believed pets do this when no other food source is available, though in some cases, eating their human has occurred even with a full food bowl. It’s something to consider the next time your cat gives you an affectionate lick on the arm. Maybe it loves you. Or maybe it has something else in mind.

[h/t The Washington Post]

7 Animals That Appear to Fly (Besides Birds, Bats, and Insects)

renacal1/iStock via Getty Images
renacal1/iStock via Getty Images

The only animals that can truly fly are birds, insects, and bats. Other animals manage to travel through the air by gliding from great heights or leaping from the depths. Here are a few.

1. Devil Rays

The devil rays, in the genus Mobula, are related to manta rays. Their wingspan can grow up to 17 feet wide, making them the second-largest group of rays after the mantas. These muscular fish can leap several feet out of the water, but no one is quite sure why they do it.

2. Colugos

These tree-dwelling gliders are sometimes called flying lemurs, but they're neither true lemurs nor do they fly. These mammals in the genus Cynocephalus are native to Southeast Asia and are about the size of a house cat. Colugos can glide up to 200 feet between trees using their patagium, or flaps of skin between their front and hind legs that extend to their tail and neck (colugos are even webbed between their toes). In the air, they can soar gracefully through the forest, but on the ground, they look like an animated pancake.

3. Flying Fish

Flying fish

There are about 40 different species of flying fish in the family Exocoetidae, although they don't fly so much as they leap from the water with a push of their powerful pectoral fins. Most of the species live in tropical waters. Fish have been observed skipping over the waves for as long as 45 seconds and 650 feet. Scientists suspect that flying fish leap into the air to escape predators.

4. Paradise Tree Snake

The paradise tree snake (Chrysopelea paradisi) lives in the rain forests of Southeast Asia. It glides from the treetops by flattening its body out to maximize surface area, wiggling from side to side to go in the desired direction. Though the idea of a flying snake may be terrifying, C. paradisi is not harmful to humans.

5. Flying Geckos

Flying geckos, a group of gliding lizards in the genus Gekko, live in the wet forests of Southeast Asia. In addition to patagia that let them parachute from tree branches, the geckos have remarkably mutable skin that camouflages them against tree trunks extremely well.

6. Wallace's Flying Frog

Wallace's flying frog (Rhacophorus nigropalmatus) is found in Malaysia and Indonesia. This frog has long webbed toes and a skin flap between its limbs which allows it to parachute—float downward at a steep angle—from the treetops. Although Wallace's flying frogs prefer to live in the forest canopy, they must descend to ground level to mate and lay eggs.

7. Flying Squirrels

Flying squirrels in the subfamily Sciurinae include dozens of species. They are native to North America and Eurasia. When it leaps from a tall tree, a flying squirrel will spread its patagium until it resembles a kite or parachute. The squirrel can steer by moving its wrists and adjusting the tautness of its skin.

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