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Proceedings of the Royal Society B

Will Wild Mice Use Running Wheels?

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Proceedings of the Royal Society B

Scientists and animal rights activists have long wondered if wheel running was a neurotic behavior exclusive to captive mice. But new research on mice in the wild shows that it's possible these rodents run for fun.

Johanna H. Meijer and Yuri Robbers, researchers at the Leiden University Medical Center in the Netherlands, placed exercise wheels outdoors in two areas—one urban, and one not accessible to the public—in partially enclosed cages to keep larger animals from knocking them over. They pointed video cameras triggered by infrared motion detectors on them. Over the course of the three years, cameras shot 200,000 clips of the wheels in motion.

After analyzing 12,000 clips, the researchers found that feral mice did, in fact, use the wheels: The cameras recorded 734 cases of mice running on the wheel in the urban area, and 232 cases in the private area, over the course of 24 months. Wheel running occurred year-round; the mice were typically juvenile. The mice spent between one and 18 minutes on the wheel. The animals got on the wheel, got off, and within minutes got back on, running away—and they always ran. They never walked.

“When I saw the first mice, I was extremely happy,” Meijer told the New York Times. “I had to laugh about the results, but at the same time, I take it very seriously. It’s funny, and it’s important at the same time.”

Though mice accounted for the vast majority of wheel running observations (88 percent), they weren't the only animal to go for a spin on the wheels: shrews, rats, slugs, frogs, and snails also hopped on (the snails, however, were excluded from the analysis, because they "caused haphazard rather than directional movement of the wheel," according to the study, which appeared in Proceedings of the Royal Society B). Like mice, some shrews, rats, and frogs left the wheel and then entered it again to keep running. "This observation indicates that wheel running may well be intentional rather than unintentional for these animals," the study says.

Though the enclosures at first had food, removing the food didn't stop mice from running. Although the researchers noted that the number of visits to the enclosures dropped after the food was removed, "the fraction of visits including wheel running increased. This implies that wheel running can be experienced as rewarding even without an associated food reward, suggesting the importance of motivational systems unrelated to foraging."

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science
6 Radiant Facts About Irène Joliot-Curie
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Hulton Archive/Getty Images

Though her accomplishments are often overshadowed by those of her parents, the elder daughter of Marie and Pierre Curie was a brilliant researcher in her own right.

1. SHE WAS BORN TO, AND FOR, GREATNESS.

A black and white photo of Irene and Marie Curie in the laboratory in 1925.
Irène and Marie in the laboratory, 1925.
Wellcome Images, Wikimedia Commons // CC BY 4.0

Irène’s birth in Paris in 1897 launched what would become a world-changing scientific dynasty. A restless Marie rejoined her loving husband in the laboratory shortly after the baby’s arrival. Over the next 10 years, the Curies discovered radium and polonium, founded the science of radioactivity, welcomed a second daughter, Eve, and won a Nobel Prize in Physics. The Curies expected their daughters to excel in their education and their work. And excel they did; by 1925, Irène had a doctorate in chemistry and was working in her mother’s laboratory.

2. HER PARENTS' MARRIAGE WAS A MODEL FOR HER OWN.

Like her mother, Irène fell in love in the lab—both with her work and with another scientist. Frédéric Joliot joined the Curie team as an assistant. He and Irène quickly bonded over shared interests in sports, the arts, and human rights. The two began collaborating on research and soon married, equitably combining their names and signing their work Irène and Frédéric Joliot-Curie.

3. SHE AND HER HUSBAND WERE AN UNSTOPPABLE PAIR.

Black and white photo of Irène and Fréderic Joliot-Curie working side by side in their laboratory.
Bibliothèque Nationale de France, Wikimedia Commons // Public Domain

Their passion for exploration drove them ever onward into exciting new territory. A decade of experimentation yielded advances in several disciplines. They learned how the thyroid gland absorbs radioiodine and how the body metabolizes radioactive phosphates. They found ways to coax radioactive isotopes from ordinarily non-radioactive materials—a discovery that would eventually enable both nuclear power and atomic weaponry, and one that earned them the Nobel Prize in Chemistry in 1935.

4. THEY FOUGHT FOR JUSTICE AND PEACE.

The humanist principles that initially drew Irène and Frédéric together only deepened as they grew older. Both were proud members of the Socialist Party and the Comité de Vigilance des Intellectuels Antifascistes (Vigilance Committee of Anti-Fascist Intellectuals). They took great pains to keep atomic research out of Nazi hands, sealing and hiding their research as Germany occupied their country, Irène also served as undersecretary of state for scientific research of the Popular Front government.

5. SHE WAS NOT CONTENT WITH THE STATUS QUO.

Irène eventually scaled back her time in the lab to raise her children Hélène and Pierre. But she never slowed down, nor did she stop fighting for equality and freedom for all. Especially active in women’s rights groups, she became a member of the Comité National de l'Union des Femmes Françaises and the World Peace Council.

6. SHE WORKED HERSELF TO DEATH.

Irène’s extraordinary life was a mirror of her mother’s. Tragically, her death was, too. Years of watching radiation poisoning and cancer taking their toll on Marie never dissuaded Irène from her work. In 1956, dying of leukemia, she entered the Curie Hospital, where she followed her mother’s luminous footsteps into the great beyond.

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You Can Now Order Food Through Facebook
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iStock

After a bit of controversy over its way of aggregating news feeds and some questionable content censoring policies, it’s nice to have Facebook roll out a feature everyone can agree on: allowing you to order food without leaving the social media site.

According to a press release, Facebook says that the company decided to begin offering food delivery options after realizing that many of its users come to the social media hub to rate and discuss local eateries. Rather than hop from Facebook to the restaurant or a delivery service, you’ll be able to stay within the app and select from a menu of food choices. Just click “Order Food” from the Explore menu on a desktop interface or under the “More” option on Android or iOS devices. There, you’ll be presented with options that will accept takeout or delivery orders, as well as businesses participating with services like Delivery.com or EatStreet.

If you need to sign up and create an account with Delivery.com or Jimmy John’s, for example, you can do that without leaving Facebook. The feature is expected to be available nationally, effective immediately.

[h/t Forbes]

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