15 Things You Might Not Know About Rhinos

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iStock

The rhinoceros is the second largest land mammal on Earth, next to the elephant. It's also one of the most aggressive. But despite its reputation as the bully on the playground, rhinos are vulnerable when it comes to one great danger: humans. Their ranks have drastically dwindled over the past century due to poaching and habitat loss, and conservationists are now trying to save them from extinction. In recognition of Save the Rhinos Day on May 1, here are 15 important facts about nature's knight in armor.

1. THEY'RE GREEK—AT LEAST IN NAME.

Rhinoceros in a field with a pond
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The word rhinoceros stems from the Greek words rhino (nose) and keras (horn). So when you shorten the word to "rhino," you're really just saying "nose."

2. A GROUP OF RHINOS IS CALLED A "CRASH."

Three rhinos drinking water
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Crash of Rhinos also happens to be an emo band from Derby, England.

3. THEY USED TO BE 16 FEET TALL.

older rhino walking with two younger rhinos
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The paraceratherium, a hornless species of ancient rhinoceros that roamed the Earth 30 million years ago, stood over 16 feet tall. Modern rhinos are significantly smaller, of course, but scientists don't really know how they evolved. The white rhino, which grows up to 6 feet tall, is the largest of the five species that exist today. Measuring under 5 feet in height, the smallest is the Sumatran rhino, which is the only hairy species as well as the closest living relative of the extinct woolly rhinoceros.

4. WHITE RHINOS AND BLACK RHINOS ARE ACTUALLY THE SAME COLOR.

two rhinos standing in grass
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They're both essentially grayish-brown. One widely spread rumor suggests that white rhinos were originally called wijd (wide) by Dutch settlers in Africa, referring to the animal's wide mouth, which was then mistranslated into English as "white." However, rhino expert Kees Rookmaaker has stated that there is no linguistic evidence to support that tale. It remains a mystery how the white rhino got its name.

5. RHINOS SAY MMWONK WHEN THEY'RE HAPPY.

Indian rhinos are known to make at least 10 distinct sounds, including honks (used during head-to-head fights), bleats (signaling submission), and moo-grunts (used between mothers and calves). Black rhinos use grunts as a greeting and make a mmwonk sound when they're content.

6. THEY HAVE A COMPLICATED RELATIONSHIP WITH THE OXPECKER BIRD.

Oxpecker bird sits on the head of a rhino
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Rhinos are often seen with oxpeckers hitching a ride on their backs, but the benefit of these birds is currently debated. The traditional argument is that they snack on bugs and ticks that crawl on the rhino's skin, but in 2000, research on cattle failed to find a consistent benefit to having oxpeckers, while a 2004 study on captive (and tick-free) rhinos found that rather than being helpful, oxpeckers spent much of their time picking at wounds and feasting on the rhino’s blood [PDF]. Meanwhile, other researchers argue that the birds actually do eat ticks and the like. The birds may give the rhinos one additional benefit though: A 2010 experiment found that without oxpeckers, black rhinos were able to detect a person walking up to a rhino 23 percent of the time. With the oxpeckers present that shot up to 97 percent, perhaps explaining why in Swahili, the oxpecker is referred to as the "rhino's guard."

7. THEY'RE LONG-DISTANCE SPRAYERS.

rhino spray urinating
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In a show of dominance, alpha male Indian rhinos can spray urine a distance of over 16 feet. This is typically done in the presence of other males or breeding-age females. Other rhinos also spray urine: For males this is typically for marking territory, while female Sumatran rhinos [PDF] have been observed spray urinating 69 times in a 12 hour period before giving birth, and continued this behavior even after the calf was weaned, likely to mask the scent of the calf.

8. THEY COMMUNICATE THROUGH POOP.

rhino sniffing poop
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White rhino droppings are unique identifiers, meaning that a rhino can take one whiff of a dung heap and instantly know the animal's age, sex, and reproductive status, according to one study. All white rhinos in a particular area head to the same spot to defecate, called a midden, which is essentially a communal dumping ground.

"We think of dung as just a waste product, but it's really a good way for animals to communicate," Courtney Marneweck, the head of the study, told National Geographic. "There's a lot of information there that we haven't taken advantage of."

9. THEIR FARTS SMELL LIKE SULFUR.

rhino sniffing another rhino's butt
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Rhinos are notorious for passing particularly noxious gas, according to the book Does It Fart? The Definitive Field Guide to Animal Flatulence:

"Rhino farts also smell really bad, so much so that they have even given rise to a piece of brewing terminology; when the yeast used to make alcohol through fermentation produces hydrogen sulfide it gives off a horrible sulfur smell, known as a rhino fart."

10. THE MALES CAN GET AGGRESSIVE.

two male rhinos fighting with their horns
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Rhinos aren't afraid to use their horns when it comes to matters of the heart. Male black rhinos are particularly aggressive in their pursuit of a mate, and the rate of "mortal combat" among these horned lovers is higher than any other mammal on the planet. About half of males and 30 percent of females die from injuries sustained while fighting.

11. THEY'RE RELATED TO ZEBRAS.

rhinos gathering with zebras
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The closest living relatives to rhinos are not elephants or hippos, but rather horses, tapirs, and zebras, all of which are classified as odd-toed ungulates. Rhinos and tapirs walk on three toes, while horses walk on one (which we know as a hoof).

12. THEY HAVE SENSITIVE FEET.

rhino's feet
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Speaking of toes, rhinos do have one weak spot. Rhinos typically put most of their weight on their toenails when they walk to avoid wearing out their sensitive feet. This is easy to do in the wild, where marshes and mushy wetlands abound, but when they're brought to zoos, their toenails tend to wear down on hard surfaces like concrete and asphalt. This can lead to swollen, sore, and cracked feet, making them more susceptible to infection. To tackle this issue, one zoo glued modified horseshoes onto a rhino's toes, which you can read about in the book The Rhino With Glue-On Shoes.

13. THEY'RE WALLOWERS.

But not because they're depressed. For a rhino, a nice mud bath is like a day at the spa. It not only helps the animals cool down in hot weather, but it's also great for their skin, helping to ward off pesky insects. Although the animals have a pretty thick dermis, they're surprisingly vulnerable when it comes to bug bites and sunburn.

14. THEIR HORNS ARE MADE OF THE SAME PROTEIN FOUND IN HUMAN FINGERNAILS.

close-up on a rhino's horns
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Rhino horns are made up of nothing but keratin, but that doesn't stop poachers from killing thousands of the animals each year and selling their horns on the black market. The horns are fashioned into jewelry and figurines, and in some parts of Asia they're believed to hold healing properties (they don't).

15. THEY RISK EXTINCTION.

man with binoculars in the wild
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Just a century ago, there were more than half a million rhinos around the world. Now, around 30,000 survive in the wild, largely due to poaching. All five species of rhino are in danger, but three are considered critically endangered: Sumatran, Javan, and black rhinos. Today, there are about 60 remaining Javan rhinos, fewer than 100 Sumatran rhinos, and about 5000 black rhinos.

There is some good news, though. Thanks to conservation efforts, black and white rhino numbers have increased in recent years, with the white rhino having been "brought back from the brink of extinction," according to the World Wildlife Fund. The organization Save the Rhinos is taking a multi-pronged approach to the issue, working to deploy more field rangers to protect the animals, reduce demand in Asia, and breed rhinos that are currently in captivity.

11 Cute Facts About Crickets

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iStock.com/sirichai_raksue

They’re insects that invade our homes, but they’re beloved around the world. They’re living thermometers with ears on their knees, and they just might save the world. Here are 11 surprising (and often adorable) facts about crickets.

1. Crickets were named for the sounds they make.

The word cricket comes from the Old French word criquet, and refers to the cricket’s song—people once thought that those repeated chirps sounded like “criquet … criquet … criquet.”

Interestingly, the name for the sport of cricket has a totally different origin: it comes from an Old French word for goal post.

2. They don't make sound the way you think they do.

How do crickets chirp? Old-timey illustrators sidestepped this question by drawing them playing tiny violins. There’s a persistent myth that crickets rub their legs together to make sound. In fact, they sing with their wings.

Run your finger down the teeth of a comb and you’ll hear an almost musical rattle. Crickets make sound in a similar way. They rub a scraping organ on one wing against a comb-like organ on the other.

Each cricket species has distinctive noise-making structures that produce unique sounds. Scientists have even managed to recreate the sound of an extinct cricket relative, a fossilized Jurassic bush cricket (katydid), by examining the shape of its wings.

3. Most female crickets don't sing.

That cricket in your house that’s endlessly chirping away? It’s probably a male. Most female crickets lack those sound-making wing structures. There are exceptions: Some female mole crickets (relatives of “true” crickets) sing. And males of some cricket species never make a peep.

So why do male crickets (usually) chirp?

4. Crickets sing out of love—and anger.

It’s all about securing a mate. But crickets don’t just sing a pretty song and wait for the admirers to trickle in. Many of them have a whole repertoire of calls: There’s one for attracting females from afar, another for close-up courtship, and even a triumphal after-mating song. Crickets also sing to intimidate rival males, and some of a male’s more romantic tunes may trigger nearby females to fight each other.

5. You can use cricket songs as a thermometer.

Crickets call more frequently when the weather gets hotter. It’s such a proven phenomenon that you can use it to calculate the temperature. The snowy tree cricket’s gentle calls seem to match the heat especially accurately. The Old Farmer’s Almanac recommends that you count the number of chirps in 14 seconds and add 40 to get the temperature in Fahrenheit.

6. Some crickets have evolved to stay silent.

A particular fly species has invaded the island of Kauai in Hawaii, and it’s the stuff of cricket nightmares: It uses its incredibly sophisticated hearing system to find a singing cricket and drop maggots on it. Those maggots burrow into their victim and devour it from the inside.

Male crickets on Kauai have responded in a remarkable way. They’ve evolved wings more like a female cricket’s, which means they’ve lost the ability to chirp. Those silent, safe crickets compensate for their lack of courtship songs by spending more time on the move [PDF], which improves their chances of running into potential mates.

7. Crickets listen with their legs.

Insects have ears in weird places. Those cricket-eating parasitic flies, for example, have ears just below their head and neck. When a butterfly lands and folds up its wings, it’s exposing its ears. And cricket ears are tiny spots, just a fraction of a millimeter long, on their front legs just below the knees. They’re some of the smallest ears of any animal, but they’re highly sensitive.

8. There's a whole rainbow of crickets.

If you’ve found a cricket in your house or yard, chances are that it’s black or brownish. But that somber insect has some pretty colorful relatives. There’s the red-headed bush cricket, also known as the handsome trig—and it’s, well, pretty handsome for a cricket. The snowy tree cricket is pastel green with wings shaped like tennis rackets. And if you visit the tropics, where there are more cricket species than anywhere else, you might spot this intricately patterned Nisitrus species.

That’s just the so-called “true” crickets, members of the family Gryllidae. People also use the word cricket for many close Gryllidae relatives, and they’re an amazing bunch of insects ...

9. Crickets have rock star relatives.

One group of cricket relatives is the mole crickets. These insects have big claws and live underground. To attract mates, they throw little rock concerts: They dig horn-shaped burrows, turning their homes into amplifiers that make their calls extra loud.

Then there are the bush crickets, or katydids, which come in hot pink and other startling hues. And some katydids look so much like leaves, complete with dried patches, chew marks, and holes, that you’ve probably walked right past them without realizing you’re being watched.

Another group of cricket relatives, New Zealand’s wetas, includes enormous insects that can outweigh a mouse. The name weta comes from a Maori word for “god of ugly things.” Weta Workshop, the company that created props, costumes, and creatures for the Lord of the Rings films, took its name from these otherworldly insects.

9. People love crickets.

Insects often get a bad rap, but people of many cultures adore crickets. Chinese people have long kept these insects as good luck charms—and for cricket-on-cricket battles. Crickets are beloved in Japan, especially for their musical songs. In Brazil, some species are considered to be signs of hope or incoming wealth (though others are thought to be omens of illness and death). Charles Dickens wrote a tale called The Cricket on the Hearth that featured a cricket acting as a household’s guardian angel. And who could forget Disney’s Jiminy Cricket, and Cri-Kee from Mulan? Few other insects have received the cute Disney treatment.

10. Crickets live in our homes.

Many types of crickets will happily live in and around houses. House crickets, which are brownish and probably native to Asia, breed inside homes in many cities around the world. Black-colored field crickets will accidentally wander into buildings. And one cricket relative, the greenhouse camel cricket, has been quietly invading residences in the eastern U.S.

Fortunately, these household crickets are mostly harmless. Their poop may stain the curtains, and in rare cases they’ll nibble clothing—but usually the worst they’ll do is annoy you with their incessant calls.

11. Crickets just might save the world.

Imagine a high-protein food that’s packed with vitamins. It’s more efficient to produce than conventional meats, and it generates way less greenhouse gas. This superfood? Yup, it’s crickets. You can now purchase these insects in a variety of forms that are mercifully free of twitching legs—including flour. If westerners can overcome their squeamishness about eating insects, then crickets just may be the future of food.

This story originally ran in 2016.

Elephants Are Evolving Without Tusks Thanks to Poaching

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iStock.com/LeighGregg

Natural selection can take millions of years to shape a gene pool, but in parts of Africa, the extreme pressures of poaching may have changed elephants in just a few decades. As National Geographic reports, more tuskless elephants have emerged in regions where their ivory has made them a target.

Elephant poaching has long been in a problem Africa, but the crisis reached a fever pitch during Mozambique's 15-year civil war. Between 1977 and 1992, 90 percent of the elephants living in the country's Gorongosa National Park were slaughtered for ivory used to fund the conflict.

The diminished numbers aren't the only thing that looks different about Gorongosa's elephants today. Poachers often kill male elephants first because they have bigger tusks, and once they're eliminated, the hunters will go after females. Typically, about 2 to 4 percent of all female African elephants never develop tusks—but among female elephants that survived Mozambique's civil war, that number is 51 percent. The effects of poaching can also be observed in the next generation. Roughly 32 percent of female elephants born after 1992 are tuskless.

The trend can be seen in other parts of Africa where poaching has ravaged elephant populations. In Ruaha National Park in Tanzania, elephant behavior researcher Josephine Smit has observed that over one fifth of female elephants older than 5 years lack tusks. Tusklessness rates reach about 35 percent in females over 25.

The statistics are even harder to ignore in South Africa's Addo Elephant National Park, where tuskless animals made up 98 percent of all female elephants in the early 2000s. South Luangwa National Park in Zambia, Lupande Game Management Area in Zambia, and Queen Elizabeth National Park in Uganda each reported higher-than-average rates of tusklessness immediately following the ivory wars of the 1970s and '80s.

Though poaching is on the decline thanks to bans on the ivory trade and other conservation efforts in Africa, its impact can still be felt. In East Africa, the elephant population was nearly halved between 2008 and 2018. The establishment of wildlife preserves, DNA tracing, and GPS tracking are just a few of the ways conservationists are working to crack down on poachers and restore the species.

[h/t National Geographic]

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