20 Black-and-White Facts About Penguins

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To celebrate World Penguin Day (which is today, April 25), here are a few fun facts about these adorable tuxedoed birds.

1. All 17 species of penguins are found exclusively in the Southern Hemisphere.

2. Emperor Penguins are the tallest species, standing nearly 4 feet tall. The smallest is the Little Blue Penguin, which is only about 16 inches.

emperor penguin
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3. The fastest species is the Gentoo Penguin, which can reach swimming speeds up to 22 mph.

Gentoo Penguin
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4. A penguin's striking coloring is a matter of camouflage; from above, its black back blends into the murky depths of the ocean. From below, its white belly is hidden against the bright surface.

penguins swimming in the ocean
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5. Fossils place the earliest penguin relative at some 60 million years ago, meaning an ancestor of the birds we see today survived the mass extinction of the dinosaurs.

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6. Penguins ingest a lot of seawater while hunting for fish, but a special gland behind their eyes—the supraorbital gland—filters out the saltwater from their blood stream. Penguins excrete it through their beaks, or by sneezing.

penguins swimming in the ocean
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7. Unlike most birds—which lose and replace a few feathers at a time—penguins molt all at once, spending two or three weeks land-bound as they undergo what is called the catastrophic molt.

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8. All but two species of penguins breed in large colonies of up to a thousand birds.

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9. It varies by species, but many penguins will mate with the same member of the opposite sex season after season.

chinstrap penguins
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10. Similarly, most species are also loyal to their exact nesting site, often returning to the same rookery in which they were born.

maegellic penguin nesting
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11. Some species create nests for their eggs out of pebbles and loose feathers. Emperor Penguins are an exception: They incubate a single egg each breeding season on the top of their feet. Under a loose fold of skin is a featherless area with a concentration of blood vessels that keeps the egg warm.

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12. In some species, it is the male penguin which incubates the eggs while females leave to hunt for weeks at a time. Because of this, pudgy males—with enough fat storage to survive weeks without eating—are most desirable.

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13. Penguin parents—both male and female—care for their young for several months until the chicks are strong enough to hunt for food on their own.

Penguins nest
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14. If a female Emperor Penguin's baby dies, she will often "kidnap" an unrelated chick.

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15. Despite their lack of visible ears, penguins have excellent hearing and rely on distinct calls to identify their mates when returning to the crowded breeding grounds.

16. The first published account of penguins comes from Antonio Pigafetta, who was aboard Ferdinand Magellan's first circumnavigation of the globe in 1520. They spotted the animals near what was probably Punta Tombo in Argentina. (He called them "strange geese.")

17. An earlier, anonymous diary entry from Vasco da Gama's 1497 voyage around the Cape of Good Hope makes mention of flightless birds as large as ducks.

18. Because they aren't used to danger from animals on solid ground, wild penguins exhibit no particular fear of human tourists.

19. Unlike most sea mammals—which rely on blubber to stay warm—penguins survive because their feathers trap a layer of warm air next to the skin that serves as insulation, especially when they start generating muscular heat by swimming around.

20. In the 16th century, the word penguin actually referred to great auks (scientific name: Pinguinus impennis), a now-extinct species that inhabited the seas around eastern Canada. When explorers traveled to the Southern Hemisphere, they saw black and white birds that resembled auks, and called them penguins.

What's the Difference Between Pigeons and Doves?

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To the layman, the difference between pigeons and doves has something to with color, maybe. Or location. Or general appeal (doves usually get much better press than pigeons do). But what’s the actual, scientific difference between doves and pigeons?

As it turns out, there isn’t one. Paul Sweet, the collection manager for the department of ornithology at the American Museum of Natural History, says the difference is more linguistic than taxonomic.

“The word dove is a word that came into English from the more Nordic languages, whereas pigeon came into English from French,” Sweet tells Mental Floss.

Both dove and pigeon refer to the 308 species of birds from the Columbidae family, Sweet says. There’s no difference between a pigeon and a dove in scientific nomenclature, but colloquial English tends to categorize them by size. Something called a dove is generally smaller than something called a pigeon, but that’s not always the case. A common pigeon, for example, is called both a rock dove and a rock pigeon.

“People just have their own classification for what makes them different,” Sweet says. “So in the Pacific, for example, the big ones might get called pigeons and the smaller ones might be called doves, but they’re actually more closely related to each other than they are to other things in, say, South America, that are called pigeons and doves.”

The difference boils down to linguistic traditions, so feel free to tell people you’re releasing pigeons at your wedding or that you’re feeding doves in the park. Scientifically speaking, you’ll be correct either way.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

8 Hair-Raising Facts About Black Cats

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No member of catkind is more maligned than the black cat. At best, they're bemoaned as lackluster photography subjects; at worst, they're seen as harbingers of really bad luck. But there's a lot to love about these furballs, as evidenced by the holidays in their honor—the ASPCA celebrates Black Cat Appreciation Day annually on August 17 and, across the pond, October 27 is National Black Cat Day—and the facts below.

1. IN SOME CULTURES, BLACK CATS ARE GOOD LUCK.

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They may have a less-than-stellar reputation in some areas of the world, but there are plenty of places where black cats aren’t bad luck at all. If you’re a single woman in Japan, owning a black cat is said to increase your number of suitors; if you’re in Germany and one crosses your path from right to left, good things are on the horizon.

2. THEY'RE A SAILOR'S BEST FRIEND.

Not only were cats welcome aboard British vessels to hunt mice, but sailors generally thought a black cat in particular would bring good luck and ensure a safe return home. A few of these kitties have been enshrined in maritime history, like Tiddles, who traveled more than 30,000 miles during his time with the Royal Navy. (His favorite pastime was playing with the capstan’s bell-rope.)

3. THERE IS NO ONE BLACK CAT BREED.

The Cat Fanciers’ Association (CFA) recognizes 22 different breeds that can have solid black coats—including the Norwegian Forest Cat, Japanese Bobtail, and Scottish Fold—but the Bombay breed is what most people picture: a copper-eyed, all-black shorthair. The resemblance to a "black panther" (more on those animals in a bit) is no coincidence. In the 1950s, a woman named Nikki Horner was so enamored with how panthers looked that she bred what we now refer to as the Bombay.

4. BLACK CATS ARE AS EASILY ADOPTED AS CATS OF OTHER COLORS.

Black cat facts.
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It’s common to think that black cats in shelters are the last in line to find their forever homes, but a recent survey from the ASPCA suggests otherwise. Although euthanasia numbers for black cats were some of the highest, their total number of adoptions was the highest of any hue as well. The vet who conducted the study argues that there may just simply be more black cats than other colors.

5. THEIR COATS CAN "RUST."

A black cat’s color all boils down to a genetic quirk. There are three variants of the black fur gene (solid black, brown, and cinnamon), and the hue works in conjunction with the pattern. If a cat has a solid black hue, but also the dominant tabby stripe gene, heavy exposure to the sun can make the eumelanin pigment in its fur break down to reveal its once-invisible stripes (another potential cause: nutritional deficiency). What was once a black cat is now a rusty brown cat.

6. THE GENE THAT CAUSES BLACK FUR MIGHT MAKE THESE FELINES RESISTANT TO DISEASE.

Even though their coloring is what gives them a bad reputation, these felines may be getting the last laugh after all. The mutation that causes a cat’s fur to be black is in the same genetic family as genes known to give humans resistance to diseases like HIV. Some scientists think the color of these cats may have less to do with camouflage and more to do with disease resistance. They’re hoping that as more cat genomes are mapped, we may get a step closer to curing HIV.

7. YOU CAN VISIT A CAT CAFE DEVOTED TO BLACK CATS.

Step through the doors of Nekobiyaka in Himeji, Japan and get ready for your wildest cat lady dreams to come true. Black cats are the stars of this café and visitors are invited to pet (but not pick up) these lithe felines. Each of Nekobiyaka’s identical-looking black cats wears a different colored bandana to resolve any catastrophic mix-ups.

8. THEY'RE DIFFICULT TO PHOTOGRAPH—BUT IT CAN BE DONE.

A black cat is photographed against a blue-gray background
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The modern-day conundrum black cat owners face isn’t bad luck, but bad lighting. In a world filled with people sharing photos of their pets on Instagram, black cats can end up looking like a dark blob in photos. One photographer’s advice? Minimalist backgrounds, so your subject can stand out, and angling them towards natural light sources (but keep them out of bright sunlight!). If you're snapping pics on your iPhone, tap on your cat's face, then use the sun icon to brighten up the photo.

BONUS: BLACK PANTHERS HAVE SPOTS.

Technically, there is no such thing as a black panther—it’s a term used for any big black cat. What we call black panthers are in fact jaguars or leopards and yes, they have spots, too. Their hair shafts produce too much melanin thanks to a mutation in their agouti genes, which are responsible for distributing pigment in an animal’s fur. Look carefully and you can see a panther’s spots as the sunlight hits them in just the right way.

This article originally ran in 2016.

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