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12 Fascinating Facts About Crows

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Crows often get a bad rap. In many Western cultures, they've historically been associated with death, disease, and bad omens, reviled as crop-stealers by farmers, and condemned as nuisances by city dwellers. But the birds are fascinating creatures, adaptable and brainy to an extent that's almost scary. Here are a few facts about the corvids that might surprise you.

1. ALL CROWS AND RAVENS BELONG TO THE SAME GENUS.

Members of the Corvus genus can be found on every continent except Antarctica and South America (although other close relatives live there). To date, scientists have named 40 species. Colloquially, some of them are referred to as ravens while others are called crows or jackdaws.

Historically, the name raven has been given to several of the big-bodied Corvus birds with shaggy feathers on their necks. Mid-sized members of the genus are usually called crows, while the very smallest species go by the name jackdaws. There's also a large-beaked outlier known as the rook, which was named after the unusual sound it makes. But pervasive as these labels may be, they're not scientific and do not reflect the latest research. Despite its informal name, the so-called Australian raven is more closely akin to the Torresian crow than it is to the common raven.

In the U.S., when people talk about crows and ravens, they're usually referring to the American crow (Corvus brachyrhynchos) and the common raven (Corvus corax). Telling them apart can be tough, but it is possible for eagle-eyed birders. One big indicator is size: The common raven is much larger, about the size of a red-tailed hawk. It also has a more wedge-shaped tail. As Kevin J. McGowan of the Cornell Lab of Ornithology writes on his crow FAQ page, ravens soar longer than crows, and you can see through their wing feathers as they fly (among other differences). And the birds' calls are substantially different. "American crows make the familiar caw-caw, but also have a large repertoire of rattles, clicks, and even clear bell-like notes," McGowan writes, whereas common ravens have "a deep, reverberating croaking or gronk-gronk. Only occasionally will a raven make a call similar to a crow's caw, but even then it is so deep as to be fairly easily distinguished from a real crow."

You can hear crow vocalizations here and raven vocalizations here.

2. OLDER SIBLINGS CAN HELP THEIR PARENTS RAISE NEWBORN CHICKS.

Like a lot of intelligent animals, most crows are quite social. For instance, American crows spend most of the year living in pairs (they usually mate for life) or small family groups. During the winter months, they'll congregate with hundreds or even thousands of their peers to sleep together at night in a sprawling communal unit called a roost.

Come nesting season, a mated pair of crows might be lucky enough to receive chick-rearing help. Juvenile birds are frequently seen defending their parents' nest from predators. Other services they can provide include bringing food to mom and dad, or feeding their younger siblings directly. One study found that 80 percent of American crow nests surveyed had a helping hand. And some birds become regular nest assistants, providing aid to their parents for over half a decade.

3. WHEN A CROW DIES, ITS NEIGHBORS MAY THROW A FUNERAL.

The sight of a dead crow tends to attract a mob of a hundred or more live ones. During this ritual, the live crows almost never touch the dead one, which rules scavenging out as a motive. Why do they do this? Some studies suggest that the mass gathering is part of a survival strategy: The birds are learning about threats and seem hesitant to revisit any spot where they've encountered a dead crow, even if food is plentiful there.

4. THEY'VE CAUSED BLACKOUTS IN JAPAN.

Since the 1990s, crows have experienced a population boom in Japan, where—not coincidentally—delicious garbage is more plentiful than ever before. This is bad news for power companies. Urban crows like to nest on electric transformers and will often use wire hangers or fiberoptic cables as building materials for their nests. The result was an epidemic of crow-caused blackouts in major cities around Japan: Between 2006 and 2008, the corvids stole almost 1400 fiberoptic cables from Tokyo power providers, and according to the Chubu electric company, crows are responsible for around 100 power failures per year in their facilities alone.

To fight back, Chubu started installing artificial "love nests" in 2004. Made with non-conductive resin, the nests are placed on company towers high above the power lines, where the birds are unlikely to cause any trouble. The strategy seems to be working: 67 percent of the faux nests are currently in use, making life a lot easier for Chubu employees.

5. PROPORTIONALLY, THE BRAINS OF SOME CROWS ARE BIGGER THAN YOURS.

According to McGowan, crows are "smarter than many undergraduates, but probably not as smart as ravens."

Crows are so smart and so good at improvising that some zoologists admiringly call them "feathered apes." And yet, from a primate's perspective, crow brains might look puny. The New Caledonian crow, for example, has a brain that weighs just 0.26 ounces. But relative to its body size, that brain is huge, accounting for 2.7 percent of the bird's overall weight. By comparison, an adult human's three-pound brain represents 1.9 percent of their body weight.

Of all the living birds, crows, ravens, and parrots have the biggest brain-to-body size ratios. And in lab experiments, these avians show a degree of cognition that puts them on par with the great apes. In fact, research has shown that they have a much higher density of neurons in their forebrains than primates do. The amount of neurons in this region is thought to correlate with a given animal's intelligence. Theoretically, having more neurons translates to better cognitive reasoning. Thus, it looks like crows, ravens, and parrots have enviable minds indeed.

6. CROWS HAVE REGIONAL DIALECTS—WHICH THEY CAN DELIBERATELY CHANGE.

Apart from the famous caw, caw noise, crows emit a number of other sounds. Each one sends out a different message; for example, cawing can be used as a territorial warning—or a way for crows to signal their location to relatives.

This avian language isn't homogeneous; two different populations of crows may have slight differences. As ornithologist John M. Marzluff and author Tony Angell noted in their 2005 book In the Company of Crows and Ravens, the calls these birds use "vary regionally, like human dialects that can vary from valley to valley." And there's more: If a crow changes its social group, the bird will try to fit in by talking like the popular guys. "When crows join a new flock," Marzluff and Angell wrote, "they learn the flock's dialect by mimicking the calls of dominant flock members."

7. CERTAIN CROWS KNOW HOW TO READ TRAFFIC LIGHTS.

In Japan, carrion crows (Corvus corone) use cars like oversized kitchen appliances. The birds have learned to take walnuts—a favorite treat—over to road intersections, where they put the hard-shelled snacks down onto the pavement. The crow then waits for a passing vehicle to smash the nut, after which it will swoop down and eat the delicious interior.

It's a risky trick, but the crows aren't usually run over because (unlike some people) they've figured out what traffic lights mean. Carrion crows wait until the light turns red before flying down to place the un-cracked nut on the road. The second the light goes green, the crow takes off to watch the nut get run over from afar; it will even wait for the next red to scoop up the nut's insides.

This behavior isn't limited to just one corvid species: American crows have been observed doing the same thing in California.

8. THEY CAN RECOGNIZE YOUR FACE—AND HOLD A GRUDGE.

You don't want a crow for an enemy. In 2011, a team from the University of Washington published a remarkable study about the brainpower of local crows. The researchers' goal was to figure out how well the birds could identify human faces. So—in the name of science—they went out and bought two Halloween masks: One resembled a caveman, the other looked like Dick Cheney. It was decided that the caveman getup would be used to threaten the birds, while the Cheney mask was relegated to control status.

At the five sites, a scientist donned the caveman mask before catching and banding some wild crows. Getting trapped is never a fun experience, and upon their release, the ex-captives loudly "scolded" their assailant with a threatening caw. Seeing this, other birds who had been sitting nearby joined in the fray, swooping down to harass the neanderthalic visitor. Over a period of several years, both masks were regularly worn by team members on strolls through all five test spots. Without fail, the caveman mask was greeted by angry scolds and dive-bomb attacks from crows—including many who'd never been captured or banded—while the birds largely ignored the Dick Cheney mask.

Amazingly, the caveman disguise continued to provoke a hostile response five years into the experiment—even though the team had stopped trapping crows after those first few site visits. And some of the birds who antagonized the mask-wearer weren't even alive back when the whole thing started. The younger crows couldn't possibly have seen the imitation caveman grab an acquaintance of theirs—but they scolded it anyway. Clearly, the grudge had been passed on; birds were still attacking the mask as recently as 2013.

The moral of this story? Mind your manners around crows. Because if you mistreat them, they won't forget you and neither will their friends—or the next generation.

9. NEW CALEDONIAN CROWS MAKE AND USE TOOLS.

Lots of non-human animals, including chimpanzees and orangutans, create useful implements which help them survive in the wild. The New Caledonian crow (Corvus moneduloides) is one of only two species on the planet that can craft its own hooks in the wild. The other is called Homo sapiens. The South Pacific avian uses the hooks—which are made from pliable twigs that the crows bend using their beaks and feet into a J-shape—to extract insects from tight crevices.

Another surprising attribute is this species' weirdly shaped maw. Unlike virtually all other birds, the New Caledonian crow has a bill that does not curve downwards. For years, the quirk went unexplained, but scientists now think that the avian's unique beak evolved to help it grasp tools more easily, as well as to better see what the tool is doing.

The New Caledonian crow isn't the only implement expert in the corvid family. In 2016, scientists at the University of St. Andrews demonstrated that the ultra-rare Hawaiian crow, or ‘Alalā (Corvus hawaiiensis), is similarly adept at using and modifying tools.

10. THE BIRDS FIGHT OFF PREDATORS BY GANGING UP ON THEM.

Crows have to deal with a menagerie of predators, such as hawks, owls, coyotes, and raccoons. To ward them off, the corvids exploit the fact that there can be strength in numbers. Upon seeing a would-be attacker, crows are known to gather en masse, with some groups consisting of a dozen birds or more. Individual crows then swoop down to deliver passing blows with their beaks, often inflicting serious bodily injury in the process. If all goes well, the target will back off—though it may kill a few of the dive-bombers before they retreat. Of course, corvids are by no means the only avians that mob would-be attackers. Swallows, chickadees, and even hummingbirds have all been documented doing this. In fact, crows are sometimes at the receiving end of mob violence as smaller songbirds often feel threatened by them and lash out collectively.

11. CORVIDS UNDERSTAND A THING OR TWO ABOUT IMPULSE CONTROL.

A 2014 study shows that at least some corvids can resist the urge for instant gratification—if you make it worth their while. The research was led by University of Göttingen graduate student Friederike Hillemann, whose team assembled five common ravens and seven carrion crows. Through careful note-taking, the scientists figured out what the favorite meal items of all 12 animals were. Then the experiment began.

With an outstretched hand, one of the researchers gave each of their birds a morsel of food. Then, the animals were shown a different piece of grub. The corvids were made to understand that if they liked the second option better, they could swap snacks—but only if they were willing to sit patiently for a certain period of time first. If a bird ate the original treat during that stretch, it forfeited the chance to trade it for a new one.

Hillemann's results showed that the crows and ravens didn't mind waiting around for an improved snack option. As such, a bird with a piece of bread was content to sit quietly if it knew that some fried pork fat would eventually be gained in the trade-off. However, if that same bird's second choice was another piece of bread, sitting tight would be pointless. So understandably, corvids who were put in this kind of situation tended to go ahead and eat whatever they'd been given. Why wait for more of the same?

12. YOU CAN CALL A GROUP OF CROWS A MURDER, BUT SOME SCIENTISTS WOULD RATHER YOU DIDN'T.

According to the Oxford English Dictionary (OED), the correct term for a group of crows is a murder, an expression bird-watchers and poets have been using since at least the 15th century, which the OED speculates may allude "to the crow's traditional association with violent death, or … to its harsh and raucous cry." But maybe it's time to come up with a replacement. McGowan hates the phrase "murder of crows." To him, it only feeds the public's negative outlook on the animals. "These birds aren't a gang of nasty villains," he wrote in the book Birdology. "These birds are just birds." McGowan would also have you know that American crows rank among "the most family-oriented birds in the world."

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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.

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

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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.

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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.

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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.

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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.

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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.

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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.

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6 Myths About Animals, Debunked
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It’s easy to think we understand animals: They’re present in every part of our culture, from the movies we watch to the clichés we use. But the way a species functions in the wild is often worlds apart from a stereotype or cartoon. This gulf between misconceptions and reality is the theme of Lucy Cooke’s new book, The Truth About Animals.

"We have a habit of viewing the animal kingdom through the prism of our own existence, and that trips us up and obscures the truth,” Cooke, a zoologist and founder of the Sloth Appreciation Society, tells Mental Floss. “I think it's time we rebrand the animal kingdom according to facts and not sentimentality.”

As Cooke examines in her book, the real world is one in which pandas are virile lovers and sloths are master survivalists. These are just a few of the myths that were debunked in The Truth About Animals.

1. PANDAS HAVE LOW SEX DRIVES.

Pandas have long been blamed for their own precarious position in the animal kingdom. The species is in danger, some people claim, because pandas are reluctant to or just plain bad at copulating. If only they would get off their furry behinds and get it on, there would be more of them.

In The Truth About Animals, Cooke debunks this modern myth. Pandas have been living in the wild for 18 million years—long before humans swooped in to act as their savior—and that wouldn’t be the case without healthy sex habits. It’s true that pandas are difficult to breed in captivity, and the several failed attempts of zoos to produce a baby panda throughout the 20th century is likely what led to this stereotype. But the bears are much more responsive to members of the opposite sex in the wild. The female chooses who she mates with, moaning from high in a bamboo tree while several males on the ground compete for her attention. Once the bears have paired off, they can have sex over 40 times in one afternoon.

2. SLOTHS ARE LAZY.

Cooke was inspired to write her book by sloths, which she describes to Mental Floss as “highly successful, highly evolved” creatures. Not everyone agrees: More than perhaps any other animal, sloths have become synonymous with laziness and sluggishness, and today they’re held up as an example of evolutionary failure.

The reality is that sloths are much more impressive than their appearance suggests. They’ve been around since 64 million years ago—earlier than wooly mammoths and saber-toothed tigers—and they have their slow and steady nature to thank for their success. Sloths have a remarkably slow digestive system and a low-calorie diet, so they expend as little energy as possible, not out of laziness, but out of survival instinct. A sloth is awake for more than half the day, and when necessary it can scramble up a tree at speeds approaching 1 mph. It spends most of its day in a still, seemingly trancelike state, but it isn’t wasting its potential: It’s conserving energy so it can maintain its dominant spot in the evolutionary tree.

3. PENGUINS ARE LOYAL LOVERS.

Emperor penguins, the most famous of the bird group, are known for splitting parenting duties between mated pairs, with the father incubating the egg while the mother gathers food for her family. This has led some to praise penguins as the reflection of ideal, moral family dynamics in the animal kingdom, but these people should probably find a different analog. Though the parents of any given chick may raise their offspring together, penguins aren’t monogamous: 85 percent of emperor penguins find a new partner from one breeding season to the next. Penguins are also some of the only animals known to exchange goods for sex. Adélie penguins need rocks to build up their nests during warmer months when meltwater threatens their eggs. With no parenting duties to distract them, bachelor penguins end up collecting more stones than they need, so some females will sometimes trade a one-off sex session for one of their pebbles.

4. VULTURES STALK DYING PREY.

Watch enough survival movies and you’re bound to see a shot of a hungry vulture trailing behind the starving protagonist, waiting for them to lie down and die. The myth that vultures stalk their prey while it’s still alive and have the power to predict death is a persistent one, but that doesn’t make it accurate. The scavengers have no interest in living animals and will only seek out meat from dead and decaying corpses. Rather than reaper-like premonitions of mortality, turkey vultures and greater and lesser yellow-headed vultures use their noses to locate their meals. They join kiwis and kakapos on the small list of birds with highly-developed olfactory glands. Without a strong sense of smell, other New World vultures and all Old World vultures primarily rely on sight to find food. Some New World vultures like black vultures have adopted a different strategy: They'll follow turkey vultures to their prey, taking advantage of their sensitive noses.

5. ALL BATS ARE RABID BLOOD-SUCKERS.

Bats may be the animals most closely associated with the horror genre. They crave blood, so the myth goes, and though a bat latched onto your neck won’t be able to suck you dry, it will likely infect you with a nasty case of rabies.

According to Cooke, there are many problems with the statement above. Bats are poor stand-ins for their fictional vampire counterparts; only three species of bats drink blood—the common vampire bat, the hairy-legged vampire bat, and the white-winged vampire bat—while most prefer fruit or insects. After climbing onto its prey, the vampire bat locates where the blood is flowing with the heat sensor on its nose, and then, using its sharp front teeth like shears, it cuts away any hair that might be blocking the skin. Rather than biting down and sucking like Dracula, the bat creates a small incision and laps up blood from the open wound. They can recognize an individual animal's breathing patterns and return to feed on it the following night, taking advantage of the reliable blood source.

Bats are rarely rabid, with just .05 percent of them carrying the disease—less than dogs or raccoons. The image of a bat getting tangled in your hair also has no basis in reality: Their sophisticated echolocation system signals them to turn long before they have a chance to collide with your head.

6. FEMALE HYENAS HAVE PENISES.

Hyena genitalia has been baffling scientists for centuries. Member of both sexes appear to have a penis, while in females there’s no external vagina to be found. Scientists originally thought that hyenas must be hermaphrodites, but the true explanation is even more unusual. Though it’s often referred to as a pseudo-penis, female hyena genitalia doesn’t produce sperm, technically making it a nearly 8-inch-long clitoris. This appendage is also saddled with all the same duties as a conventional female organ, including giving birth to hyena pups.

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