CLOSE
Original image

The Horrors of Anglerfish Mating

Original image

Wikimedia Commons

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 following. 

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 six or seven 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.”

Original image
iStock
arrow
Big Questions
Why Do Dogs Howl at Sirens?
Original image
iStock

A dog's behavior can often prove confusing to their human colleagues. We know they like to eat their own poop, but puzzle at their motivations. We're surprised when dogs give a ladybug the same greeting as a home intruder.

Topping the list of eccentric canine behavior: Why do dogs howl at sirens? Is there some genetic predisposition to responding to a high-pitched alarm from passing ambulances or police vehicles?

As it turns out, the reason dogs howl at sirens is because of their ancestry—namely, the wolf. When members of a pack are fractured and spread out, their companions will howl to provide a way of locating them. Think of it as nature’s GPS: By howling, dogs are able to communicate their respective locations to one another, even across long distances.

Since dogs really don’t know what a cop car is supposed to sound like, they’ll often interpret a siren as an animal’s howl. It’s also possible that dogs consider sirens to be a sign that something is abnormal in their environment, and that they want you, the pack leader, to be aware of it.

Contrary to belief, a dog is rarely howling because the noise hurts their delicate ears. If that were the case, some experts say, then they would display other behaviors, like running and hiding.

The more a dog hears and responds to a siren, the more they might be compelled to continue the behavior. That’s because dogs who howl and then notice the sound drifting away might begin to associate their vocalizing with the disappearance of the noise. In the future, they’ll probably recall that they “drove” the interloper away with their warbling and repeat the process.

While howling is usually harmless, sometimes it can be a sign that your pet is feeling separation anxiety from an owner or that they’re feeling unwell. If howling persists even without a screaming siren within earshot, you might consider taking them in for a check-up.

If you’ve wondered why dogs howl at sirens, now you know. It’s simply a way of signaling their location and not because it pains them. Owners, on the other hand, might feel differently.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

arrow
Animals
5 Ways to Keep Your Dog Calm on the Fourth of July

The Fourth of July can be rough for dogs. Fireworks displays light up their senses with unfamiliar noises, flashes, and smells, and parties flood their homes with strange guests who may invade the rooms they usually have as private retreats. And when distressed dogs escape, howl, or thrash around the house, Independence Day can quickly become a nightmare for their owners, too. To minimize Fido's stress this holiday, we spoke to some dog experts to discover the best ways to keep your canine calm on the Fourth of July.

1. EXERCISE

Anthony Newman, the dog whisperer who runs New York City's Calm Energy Dog Training, says that exercise is a great way to help your dog let off some nervous energy. “Whenever Fido is going to be neglected for an extended period of time, or around any stressful stimuli, it always helps to tire him out just before—and even during the night if you can,” Newman says. “As the saying goes, a tired dog is a good dog! He’ll be calmer, happier, and more peaceful.”

2. STAY INDOORS

Dr. Stephanie Liff, head veterinarian at Pure Paws Veterinary Care, says the best place to keep your pet during a fireworks show is inside and away from the windows. “If the pet is very scared, an escape-proof crate or a sound-insulated room, such as an internal bathroom, may help the pet to feel more secure,” Liff tells us. “If you cannot keep your pet inside, make sure that the pet is prevented from escape (monitor all exits and tell guests to monitor your pet).”

3. SOCIALIZE

While your dog may feel more secure in a room away from all the noise, Newman points out that keeping your dog isolated in another room for too long can be stressful for your pet. “Release his curiosity and let him in on the fun, to run around and play with both two-legged as well as four-legged guests,” Newman says. “Then back to his obedient room, bed, car, crate, or spot. Rinse and repeat as needed throughout the night."

4. TAKE CONTROL

According to Newman, the best way to keep your dog calm during the chaos of July 4th is to stay in charge. “If your dog winces, shivers, and runs away at loud noises, the last thing he wants is to feel like nobody else is looking out for him,” Newman says. Don’t let your dog run rampant around the house or follow him around trying to soothe him. Instead, Newman says it's important to “take control by attaching a super-light leash that you can grab and lead him whenever you need.”

5. MEDICATE

In extreme cases of nervousness, Liff says that you should talk to your vet about medication to sedate your dog.

SECTIONS

More from mental floss studios