Q: Do marine mammals, such as whales, dolphins and seals, yawn? And if so, why?
— Robert Allen | Colfax, California
Pretty much all vertebrates yawn, says Rachel Metz, a curator at the Smithsonian’s National Zoo. Among marine mammals, pinnipeds, such as seals, do—but cetaceans, such as whales and dolphins, do not. They differ from other mammals in that they breathe through blowholes instead of noses or mouths, and they are conscious breathers, meaning they have to remember to breathe, even while sleeping. As for why mammals yawn, scientists still aren’t sure why—it could be sleepiness, boredom, a need to oxygenate the brain or some other cause.
Q: Can bees and wasps differentiate between real and artificial sweeteners?
— Carol Crass | Kansas City, Missouri
The question hasn’t been formally studied in these species, but watchful apiarists say their bees show no interest in artificial sweeteners, says Seán Brady, a scientist at the National Museum of Natural History. The bees likely can sense that those sweeteners don’t contain the natural sugars found in nectar, which they use to make honey. Wasps drawn to artificial sweeteners, such as those found in sodas, might be interested in the carbohydrates and amino acids in those substances. (They don’t make honey.) Formal studies have shown that the sweetener erythritol, which is approved for human consumption, can be fatal to fruit flies, suggesting it could be used as an insecticide.
Q: What led Maine to become the first state to ban alcohol sales, in 1851—almost 70 years before the 18th Amendment banned sales nationwide?
— Joyce Ian | Catonsville, Maryland
Broadly speaking, it was the same force that powered local temperance movements and the drive for prohibition: the rise of a rural, Protestant middle class alarmed by people’s drinking habits, says Jon Grinspan, a curator at the National Museum of American History. As the U.S. expanded west in the 1820s, farmers found it more profitable to ship their grain east in the form of whiskey; in 1830, the average American—even counting children and the elderly—was drinking five gallons of hard liquor annually. Middle-class evangelicals, hoping to curb drinking and exert power over the lower class, drove the Maine effort. Ohio and Illinois were also early and durable centers of anti-drinking sentiment.
Q: What keeps all the satellites and pieces of space junk orbiting Earth from crashing into one another?
— Rebecca Adams | Natchez, Mississippi
So far, it has been luck—lower-Earth orbit, where most of these objects are, is vast. But that doesn’t mean we can keep hurling things into space, warns Martin Collins, curator at the National Air and Space Museum. There are now some 170 million man-made objects bigger than a millimeter traveling through space at 17,500 miles per hour, and some of them are the size of a school bus. Even very small pieces can be dangerous: In 2016, a paint fleck or metal fragment less than a millimeter across put a divot in an International Space Station window. Scientists are actively looking into cleaning up space debris. It’s no simple task, but a magnetic device might be the answer.