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The U.S. Army's Plans for WWII Bat Bombs

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Dan Lewis runs the popular daily newsletter Now I Know ("Learn Something New Every Day, By Email"). To subscribe to his daily email, click here.

During the final days of World War II, the United States, apparently believing that Japan was unlikely to surrender otherwise, dropped atomic bombs on Hiroshima and Nagasaki. The death toll from these two bombs numbered as high as 250,000 when factoring in those who died up to four months later due to things like burns and radiation sickness. Research into the creation of an atomic bomb began in 1939, and the Manhattan Project, which developed the science behind the weapons in earnest, began in June of 1942. But in March of 1943, the United States was developing another weapon that would have potentially spared many thousands of lives.

Unless, that is, you count the lives of the million or so bats which would have died in the process.

In the mid-1940s, many Japanese buildings were still constructed out of wood and paper, which, of course, were flammable. If the U.S. could figure out a way to start fires in a large number of buildings spread out over a wide area, the Japanese infrastructure and economy would suffer but the direct loss of life would be relatively small. But that seemed impossible. Napalm strikes could start fires everywhere in their path, but that wouldn’t spread. And carpet bombing with many small warheads would increase the area of the strike, but most likely wouldn’t cause many fires. And of course, the death toll from either of those routes could still be rather large.

But a few months before the Manhattan Project got underway, a dental surgeon named Lytle Adams came up with the idea to use bats—the nocturnal flying mammals—as part of the strategy. As he would later tell Air Force magazine, after seeing millions of bats flying around caves in Carlsbad Canyon, New Mexico, he immediately thought that they could be used as a way to spread firebombs throughout Japan. He collected a few of them himself, did a little research, and found that even tiny bats weighing well under a pound could carry three times their weight in explosives. He pitched his plan to the military (which apparently was not uncommon at the time) and the military agreed that there was something more to look into.

Adams’ theory was straightforward. Collect a million bats and strap timed incendiary devices to their backs while they hibernated. Stick a thousand of them each into a thousand bombs designed to open at high altitudes. Fly over Japan at night, drop the bombs, and then let the bats fly around. When daybreak comes, the theory went, the bats will hide in dark places—and given where they are, the most common hiding place will be attics. The timer ticks down shortly after and, without obvious explanations, hundreds of thousands of Japanese buildings start to burn to the ground.

The idea was not just a theory, either. By March of 1943, the U.S. military had identified a suitable population of bats, having located a series of caves in Texas which was the home to millions of the flying critters.  For the next year or so, at the expense of $2 million ($25 million in today’s dollars), they tested Adams’ theory. At one point, some bats got loose resulting in a major fire at the base. The military believed that the bat bombs could actually work. One report placed their effectiveness at ten to thirty times more effective (measured by the number of fires which would have started) than conventional incendiary devices.

But the final report on the bat bombs issued in mid-1944, while positive, noted that they would not be ready for combat for another year. Due to the slow time table, the military canceled the project before it could be fully developed.

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Animal Welfare Groups Are Building a Database of Every Cat in Washington, D.C.
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There are a lot of cats in Washington, D.C. They live in parks, backyards, side streets, and people's homes. Exactly how many there are is the question a new conservation project wants to answer. DC Cat Count, a collaboration between Humane Rescue Alliance, the Humane Society, PetSmart Charities, and the Smithsonian Conservation Biology Institute, aims to tally every cat in the city—even house pets, The New York Times reports.

Cities tend to support thriving feral cat populations, and that's a problem for animal conservationists. If a feline is born and grows up without human contact, it will never be a suitable house cat. The only options animal control officials have are to euthanize strays or trap and sterilize them, and release them back where they were found. If neither action is taken, it's the smaller animals that belong in the wild who suffer. Cats are invasive predators, and each year they kill billions of birds in the U.S. alone.

Before animal welfare experts and wildlife scientists can tackle this problem, they need to understand how big it is. Over the next three years, DC Cat Count will use various methods to track D.C.'s cats and build a feline database for the city. Sixty outdoor camera traps will capture images of passing cats, relying on infrared technology to sense them most of the time.

Citizens are being asked to help as well. An app is currently being developed that will allow users to snap photos of any cats they see, including their own pets. The team also plans to study the different ways these cats interact with their environments, like how much time pets spend indoors versus outdoors, for example. The initiative has a $1.5 million budget to spend on collecting data.

By the end of the project, the team hopes to have the tools both conservationists and animal welfare groups need to better control the local cat population.

Lisa LaFontaine, president and CEO of the Humane Rescue Alliance, said in a statement, “The reality is that those in the fields of welfare, ecology, conservation, and sheltering have a common long-term goal of fewer free-roaming cats on the landscape. This joint effort will provide scientific management programs to help achieve that goal, locally and nationally."

[h/t The New York Times]

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How Does Catnip Work?
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If you have a cat, you probably keep a supply of catnip at home. Many cats are irresistibly drawn to the herb, and respond excitedly to its scent, rubbing against it, rolling around on the floor, and otherwise going nuts. There are few things that can get felines quite as riled up as a whiff of catnip—not even the most delicious treats. But why does catnip, as opposed to any other plant, have such a profound effect on our feline friends?

Catnip, or Nepeta cataria, is a member of the mint family. It contains a compound called nepetalactone, which is what causes the characteristic catnip reaction. Contrary to what you might expect, the reaction isn’t pheromone related—even though pheromones are the smelly chemicals we usually associate with a change in behavior. While pheromones bind to a set of specialized receptors in what’s known as a vomeronasal organ, located in the roof of a cat's mouth (which is why they sometimes open their mouths to detect pheromones), nepetalactone binds to olfactory receptors at the olfactory epithelium, or the tissue that lines the mucus membranes inside a cat’s nose and is linked to smell.

Scientists know the basics of the chemical structure of nepetalactone, but how it causes excitement in cats is less clear. “We don’t know the full mechanisms of how the binding of these compounds to the receptors in the nose ultimately changes their behavior,” as Bruce Kornreich, associate director of the Cornell Feline Health Center, tells Mental Floss. Sadly, sticking a bunch of cats in an MRI machine with catnip and analyzing their brain activity isn’t really feasible, either from a practical or a financial standpoint, so it’s hard to determine which parts of a cat’s brain are reacting to the chemical as they frolic and play.

Though it may look like they’re getting high, catnip doesn’t appear to be harmful or addictive to cats. The euphoric period only lasts for a short time before cats become temporarily immune to its charms, meaning that it’s hard for them to overdo it.

“Cats do seem to limit themselves," Michael Topper, president of the American Veterinary Medical Association, tells Mental Floss. "Their stimulation lasts for about 10 minutes, then it sort of goes away.” While you may not want to turn your house into a greenhouse for catnip and let your feline friend run loose, it’s a useful way to keep indoor cats—whose environment isn’t always the most thrilling—stimulated and happy. (If you need proof of just how much cats love this herb, we suggest checking out Cats on Catnip, a new book of photography from professional cat photographer Andrew Martilla featuring dozens of images of cats playing around with catnip.)

That said, not all cats respond to catnip. According to Topper, an estimated 70 percent of cats react to catnip, and it appears to have a genetic basis. Topper compares it to the genetic variation that causes some individuals to smell asparagus pee while others don’t. Even if a cat will eventually love the smell of catnip, it doesn’t come out of the womb yearning for a sniff. Young kittens don’t show any behavioral response to it, and may not develop one until several months after birth [PDF].

But some researchers contend that more cats may respond to catnip than we actually realize. In one 2017 study, a group of researchers in Mexico examined how cats might subtly respond to catnip in ways that aren’t always as obvious as rolling around on the floor with their tongue hanging out. It found that 80 percent of cats responded to catnip in a passive way, showing decreased motor activity and sitting in the “sphinx” position, an indicator of a relaxed state.

There are also other plants that have similar effects on cats, some of which may appeal to a wider variety of felines than regular old catnip. In a 2017 study in the journal BMC Veterinary Research, researchers tested feline responses to not just catnip, but several other plants containing compounds similar in structure to nepetalactone, like valerian root, Tatarian honeysuckle, and silver vine. They found that 94 percent of cats responded to at least one of the plants, if not more than one. The majority of the cats that didn’t respond to catnip itself did respond to silver vine, suggesting that plant might be a potential alternative for cats that seem immune to catnip’s charms.

Despite the name, domestic cats aren’t the only species that love catnip. Many other feline species enjoy it, too, including lions and jaguars, though tigers are largely indifferent to it. The scent of the plant also attracts butterflies. (However, no matter what you’ve heard, humans can’t get high off it. When made into a tea, though, it reportedly has mild sedative effects.)

The reason Nepeta cataria releases nepetalactone doesn’t necessarily have to do with giving your cat a buzz. The fact that it gives cats that little charge of euphoria may be purely coincidental. The chemical is an insect repellant that the plant emits as a defense mechanism against pests like aphids. According to the American Chemical Society, nepetalactone attracts wasps and other insect predators that eat aphids, calling in protective reinforcements when the plant is in aphid-related distress. That it brings all the cats to the yard is just a side effect.

Because of this, catnip may have even more uses in the future beyond sending cats into a delighted frenzy. Rutgers University has spent more than a decade breeding a more potent version of catnip, called CR9, which produces more nepetalactone. It’s not just a matter of selling better cat toys; since catnip releases the compound to ward off insects, it’s also a great mosquito repellant, one that scientists hope can one day be adapted for human use. In that case, you might be as excited about catnip as your cat is.

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