What Spitting Cobras are Aiming For

iStock / Vadimborkin
iStock / Vadimborkin

Make most cobras angry, and they’ll bite you and inject the bite with a dose of venom. Frighten or tick off a spitting cobra, though, and it will contract the muscles around its venom glands and “spit” it out through holes in the tips of its fangs. Right into your face. 

Spitting cobras are no slouches when it comes to marksmanship. Neurobiologist Bruce Young found this out when he put on a plastic face mask a few years ago and taunted cobras into taking more than a hundred shots at him. When he analyzed the snakes’ movements, he found that they always spit right after he made a jerky movement with his head. The snakes would turn their heads in the same direction that he’d started to move his and then start spitting. Tracking the target like this, Young wrote in his study, “gives cobras a distinct geometric advantage; even relatively large linear movements on the part of the target can be accommodated by rather modest angular movements of the cobra's head.” A burst of speed when turning their heads also lets the snakes “lead” the target a little and compensate for the time it takes for their muscles to send the venom flying. 

It’s a cool tactic, but not as easy as just biting whatever it is that needs biting. You see, spitting cobra’s venom doesn’t do anything if it just hits you on the skin or even gets in your mouth. To be of any use, the venom has to get in your eye, where it causes searing pain and can scar the corneas and leave you blind.

This has had many biologists wondering if the cobras know to shoot for the eyes and are aiming at them. Given the snakes’ accuracy when spitting and the limited targets that their venom is effective on, scientists, zookeepers and others who study and work with spitting cobras assumed they were. In 2005, researchers from the University of Bonn in Germany backed these assumptions up with an experiment. They put undergrad student Katja Tzschätzsch face-to-face with 10 different cobras and got them to spit at her hands, her face and life-sized photos of faces. Hands and still faces and photos didn’t get a rise out of the snakes, but a moving face (real and fake) did—less so when the eyes were digitally removed from the photos than when they were left intact. When the researchers looked at the traces of venom on the photos and Tzschätzsch’s facemask, they found that the different cobras hit the eyes anywhere from 80 percent to 100 percent of the time.

Now a newer study suggests that maybe the cobras aren’t so picky when choosing their targets. Guido Westhoff, a neurobiologist who worked with Young and Tzschätzsch on the previous research, revisited the question last year with another round of experiments. He and his team presented cobras with life-size, human face-shaped boards with and without different kinds of glass eyes, as well as larger and smaller fake faces and triangular boards that didn’t resemble faces. 

In 324 spitting tests, the snakes didn’t spit at the boards with eyes any more than the ones without. Also, when the eyes on the targets were moved closer together or farther apart, the snakes didn’t adjust their aim to account for the distance between them. Given a choice between a face with eyes and an eyeless one, the snakes spit at the larger target most of the time, whether it had eyes or not. 

Westhoff now thinks that cobras don’t specifically aim for the eyes, but for the center of whatever body part their tormenter puts closest to them. Often, this just happens to be the face—and it seems the snakes prefer more face-like round targets than pointy ones; they spit at those almost four times as much—and at least one eye gets hit by chance. 

What’s more, he thinks that aiming for the eyes is both unnecessary and even a bad strategy for the snakes. Cobras can spray their venom over a wider area by moving their head as they spit and spitting several times in a row, increasing their chances of hitting the eye and without requiring them to aim right at them. Shooting for eyes instead of just a face also puts a cobra at a disadvantage if it can’t clearly see or recognize eyes, like when their own eyes become cloudy while they shed their skins, or in the dark. 

Want to Give a Retired Police or Military Dog a Forever Home? Mission K9 Rescue Can Help

Mission K9 Rescue
Mission K9 Rescue

Over the course of their careers, working dogs perform lifesaving duties while assisting members of the police force and military. These dogs receive a lot of appreciation while they're on the job, but as they enter retirement, they're often forgotten in animal shelters. An organization called Mission K9 Rescue is dedicated to placing these dogs in loving forever homes after they've served the United States.

"Our mission is to give K9 veterans—and other working dogs who have served our country—safe, peaceful, and loving homes upon retirement from service," K9 co-founder and president Kristen Maurer tells Mental Floss. "There are so many animal-loving patriots in America, and most don't realize that many of these brave, selfless dogs often remain overseas much longer than needed when they are no longer able to work. Some do not receive adequate care. We bring awareness of their plight to the public, and we work tirelessly to rescue, reunite, re-home, rehabilitate, and repair these dogs so they can live out the rest of their days in a safe and comfortable environment."

Many retired dogs are abandoned in kennels—both in the U.S. and abroad—but for some, the situation is even more severe. According to Mission K9 Rescue, working dogs are sometimes euthanized en masse when they can no longer do their jobs. The organization aims not only to remove these dogs from harm's way, but to find them forever families that are a perfect fit for them.

After rescuing dogs from both the U.S. and overseas, Mission K9 Rescue matches them with new owners. If the dog has a past handler who is interested in adopting them permanently, reuniting the pair is a priority. For all other cases, the organization goes through a rigorous process to find dogs a brand-new home.

Mission K9 also specializes in rehabilitating dogs who have suffered either mental trauma or physical injuries in their work. Just like humans, canines can develop PTSD from working in stressful, high-pressure situations. After they're rescued, animals are given as much time as they need to decompress and reintegrate into society before they're adopted. On top of the mental demands, being a working dog causes physical strain, and Mission K9 provides medical care to dogs with injuries and other issues.

Anyone can apply to adopt a retired working dog from Mission K9 Rescue. If you're interested in bringing one into your home, you can fill out the application on the group's website.

German shepherd in a bed at home.
Mission K9 Rescue

Two dogs in the backseat of a car.
Mission K9 Rescue

Dog and owner in front of home.
Mission K9 Rescue

Some Fish Eggs Can Hatch After Being Pooped Out by Swans

iStock/olaser
iStock/olaser

A question that’s often baffled scientists is how certain species of fish can sometimes appear—and even proliferate—in isolated bodies of water not previously known to harbor them. A new study has demonstrated that the most unlikely explanation might actually be correct: It’s possible they fell from the sky.

Specifically, from the rear end of a swan.

A study in the journal Ecology by researchers at the Unisinos University in Brazil found that killifish eggs can, in rare cases, survive being swallowed by swans, enduring a journey through their digestive tracts before being excreted out. This kind of fecal public transportation system explains how killifish can pop up in ponds, flood waters, and other water bodies that would seem an unlikely place for species to suddenly appear.

After discovering that some plants could survive being ingested and then flourish in swan poop, researchers took notice of a killifish egg present in a frozen fecal sample. They set about mixing two species of killifish eggs into the food supply of coscoroba swans living in a zoo. After waiting a day, they collected the poop and dug in looking for the eggs.

Of the 650 eggs they estimated to have been ingested by the swans, about five were left intact. Of those, three continued to develop. Two died of a fungal infection, but one survived, enduring 30 hours in the gut and hatching 49 days after being excreted.

Because killifish eggs have a thick outer membrane, or chorion, they stand a chance of coming through the digestive tract of an animal intact. Not all of what a swan ingests will be absorbed; their stomachs are built to extract nutrients quickly and get rid of the whatever's left so the birds can eat again. In rare cases, that can mean an egg that can go on to prosper.

Not all fish eggs are so durable, and not all fish are quite like the killifish. Dubbed the "most extreme" fish on Earth by the BBC, killifish have adapted to popping up in strange environments where water may eventually dry up. They typically live for a year and deposit eggs that can survive in soil, delaying their development until conditions—say, not being inside a swan—are optimal. One species, the mangrove killifish, can even breathe through its skin. When water recedes, they can survive on land for over two months, waddling on their bellies or using their tails to "jump" and eat insects. A fish that can survive on dry land probably doesn't sweat having to live in poop.

The researchers plan to study carp eggs next to see if they, too, can go through a lot of crap to get to where they’re going.

[h/t The New York Times]

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