Mickey Samuni-Blank via Wikimedia Commons // CC BY-SA 3.0
Mickey Samuni-Blank via Wikimedia Commons // CC BY-SA 3.0

Spiny Mice Are First Known Rodents to Have Menstrual Periods

Mickey Samuni-Blank via Wikimedia Commons // CC BY-SA 3.0
Mickey Samuni-Blank via Wikimedia Commons // CC BY-SA 3.0

Periods are a strange phenomenon. We don’t know why humans have them, or, to look at it another way, why most other animals don’t. Scientists say only 1.5 percent of mammal species have periods, and most of those are primates like us. The ranks of the menstrually afflicted grew a little bit recently, as researchers learned that female spiny mice have periods, too. They shared their findings on the bioRxiv preprint server.

The spiny mouse (Acomys cahirinus, also known as the Egyptian spiny mouse) is a perculiar little animal. It has spines like a hedgehog and will indiscriminately devour just about anything in its path, including mummified bodies. When in danger, a spiny mouse can shed (and later regrow) large chunks of its fragile skin. Needless to say, the spiny mouse has got scientists’ attention.

Curious about the spiny mouse’s reproductive system, researchers decided to get up close and personal with their nether regions. They brought 14 young, never-pregnant female mice into the lab and, once a day for 18 days, administered tiny saline douches into the rodents’ vaginas, watching to see what, if anything, would be washed out.

They found blood. Once every nine days, for about three days, the mice shed the lining of their endometrium and expelled it, along with some blood, just like humans do. The mice spent between 20 to 40 percent of their nine-day cycle menstruating, which is approximately the same proportion seen in human women. These findings make the spiny mouse the first known rodent with a human-like menstrual period.

Reproductive biologist Francesco DeMayo of the U.S. National Institute of Environmental Health Sciences was not involved with the study, but was impressed by the results. “When you do science you’re not surprised at anything—but wow, this was a really interesting finding,” he told Scientific American.

The discovery has implications not only for the rest of the animal kingdom (how many other menstruating species have scientists overlooked?) but for us. At the moment, the most popular animals used in research—mice, rats, birds, and fish—are period-free, which means they can’t be used to study the menstrual cycle. Learning about mouse menstruation could one day help us understand our own.

Why did it take scientists so long to notice that these curious creatures were part of the period posse? “The answer, as with many discoveries in science, is that no one really looked,” said Hayley Dickinson, a reproductive physiologist and long-time spiny rat researcher at the University of Monash. “Everyone knew that rodents didn't menstruate.”

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Mark Ralston, AFP/Getty Images
How a Hairdresser Found a Way to Fight Oil Spills With Hair Clippings
Mark Ralston, AFP/Getty Images
Mark Ralston, AFP/Getty Images

The Exxon Valdez oil tanker made global news in 1989 when it dumped millions of gallons of crude oil into the waters off Alaska's coast. As experts were figuring out the best ways to handle the ecological disaster, a hairdresser from Alabama named Phil McCroy was tinkering with ideas of his own. His solution, a stocking stuffed with hair clippings, was an early version of a clean-up method that's used at real oil spill sites today, according to Vox.

Hair booms are sock-like tubes stuffed with recycled hair, fur, and wool clippings. Hair naturally soaks up oil; most of the time it's sebum, an oil secreted from our sebaceous glands, but it will attract crude oil as well. When hair booms are dragged through waters slicked with oil, they sop up all of that pollution in a way that's gentle on the environment.

The same properties that make hair a great clean-up tool at spills are also what make animals vulnerable. Marine life that depends on clean fur to stay warm can die if their coats are stained with oil that's hard to wash off. Footage of an otter covered in oil was actually what inspired Phil McCroy to come up with his hair-based invention.

Check out the full story from Vox in the video below.

[h/t Vox]

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Bristly
A New Chew Toy Will Help Your Dog Brush Its Own Teeth
Bristly
Bristly

Few pet owners are willing to sit down and brush their pet's teeth on a regular basis. (Most of us can barely convince ourselves to floss our own teeth, after all.) Even fewer pets are willing to sit calmly and let it happen. But pet dental care matters: I’ve personally spent more than $1000 in the last few years dealing with the fact that my cat’s teeth are rotting out of her head.

For dog owners struggling to brush poor Fido’s teeth, there’s a slightly better option. Bristly, a product currently being funded on Kickstarter, is a chew toy that acts as a toothbrush. The rubber stick, which can be slathered with doggie toothpaste, is outfitted with bristles that brush your dog’s teeth as it plays.

A French bulldog chews on a Bristly toy.
Bristly

Designed so your dog can use it without you lifting a finger, it’s shaped like a little pogo stick, with a flattened base that allows dogs to stabilize it with their paws as they hack at the bristled stick with their teeth. The bristles are coated in a meat flavoring to encourage dogs to chew.

An estimated 80 percent of dogs over the age of 3 have some kind of dental disease, so the chances that your dog could use some extra dental attention is very high. In addition to staving off expensive vet bills, brushing your dog's teeth can improve their smelly breath.

Bristly comes in three sizes as well as in a heavy-duty version made for dogs who are prone to ripping through anything they can get their jaws around. A Bristly stick costs $29 and is scheduled to start shipping in October. Get it here.

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