7 Pairs of Commonly Confused Animals—And How to Tell the Difference

Moth (left, iStock); Butterfly (right, iStock)
Moth (left, iStock); Butterfly (right, iStock)

It’s hard to tell some animal species apart. Is that a jaguar glaring balefully at you from the shadows, or a leopard? A lizard slithering on the ground, or a salamander? Fear not—we’ve got you covered. Here are some (almost) fool-proof methods for distinguishing between seven pairs of critters.

1. MOTHS VS. BUTTERFLIES

This one might seem like a no-brainer. Most people think of butterflies as colorful garden visitors, whereas those drab moths only emerge at night to bonk against your porch light. But not so fast.

Moths and butterflies belong to the scientific order Lepidoptera—and it’s a huge, spectacularly diverse group, with tons of species that defy your expectations. Some moths fly during the day, hovering at flowers and drinking nectar. Moths can be spectacularly colorful, like this Madagascar sunset moth. And there are plenty of dull-colored butterflies, such as the brown-grey common ringlet and the grayish Avalon hairstreak.

So how can you tell them apart? One of the best methods is to look at the antennae (those long appendages that stick out from the head). With some exceptions, butterflies have a thickened part at the end of the antennae. Moth antennae, on the other hand, are usually slender or feathery and taper to a point.

2. DOLPHINS VS. PORPOISES

Bottlenose Dolphin (left, Wikimedia Commons); Harbor Porpoise (right, Wikimedia Commons)

You might have heard people use these words interchangeably, but dolphins and porpoises are very different. First off, there are way more dolphins than porpoises. The ocean dolphin family Delphinidae contains approximately 32 species, including bottlenose dolphins (like Flipper) and killer whales (like Shamu). But there are only about seven species in the porpoise family Phocoenidae. And there may soon be just six—one species, the panda-like vaquita, is nearly extinct.

In general, porpoises and dolphins have different body shapes. Porpoises tend to have rounded faces, chunky bodies, and triangular dorsal (back) fins. Many dolphins, on the other hand, have pointy faces, slender bodies, and curved dorsal fins. But there are exceptions—Risso’s dolphins, for example, have blunt heads.

Another distinguishing feature is tooth shape. Porpoise teeth are spade-shaped and dolphin teeth are cone-shaped. But that’s pretty hard to see unless you stick your head in their mouths.

3. SHEEP VS. GOATS

Sheep (left, iStock); Goat (right, iStock)

Domestic sheep and goats are both cloven-hoofed, four-legged critters with soft muzzles and really strange eyes. Here’s an easy way to tell them apart: look at the tail. Goats usually hold their tails up, whereas sheep tails hang down.

They also have different eating habits. Sheep, like cows, are grazers—they move across a pasture like fluffy vacuum cleaners, scarfing down vegetation close to the ground. Goats, on the other hand, are browsers. They pick and choose their bites from plants that are a little higher up. They’ll even climb trees for choice morsels.

4. LIZARDS VS. SALAMANDERS

Lizard (left, iStock); Salamander (right, iStock)

Lizards and salamanders look a lot alike. They have long bodies and tails, and they generally crawl around on four legs. But looks can be deceiving. Lizards and salamanders are only distantly related; in fact, lizards are closer cousins to humans than they are to salamanders.

Lizards are reptiles, like snakes and turtles. Salamanders, on the other hand, are amphibians, like frogs. Look closely and you’ll see major differences: lizards have claws on their feet, but salamanders don't (although there are one or two exceptions). Salamanders also lack scales; their skin is often smooth, moist, and slimy. Many species lack internal lungs, so their skin functions as an inside-out lung.

5. HEDGEHOGS VS. PORCUPINES

Hedgehog (left, iStock); Porcupine (right, iStock)

Let’s start with the basics: hedgehogs and porcupines are spiny. Those spines are made of special hardened hairs with hollow centers. But that’s about all these critters have in common. They aren’t closely related, and they evolved spines separately. And here’s the strange part: there are two groups of porcupine species—New World and Old World types—and they each evolved spines on their own. It’s just a useful evolutionary strategy!

Hedgehogs’ closest relatives resemble spineless hedgehogs; they’re mammals called gymnures and moonrats. Porcupines, however, belong to the order Rodentia—they are rodents. They may not look very rodent-y, but check out their big front teeth.

Porcupines use those chisel-like teeth to eat vegetation. Hedgehogs, on the other hand, have pointy teeth and snouts, and they’re omnivores, chowing down on frogs, insects, fruit, and more.

Hedgehog species inhabit parts of Europe, Africa, and Asia, but they’re not found in North and South America—so if you see a spiky animal in the New World, it’s a porcupine.

6. CROCODILES VS. ALLIGATORS

Saltwater crocodile (left, Wikimedia Commons); American alligator (right, Wikimedia Commons)

Alligators and crocodiles have a similar appearance, so it’s not surprising that they’re related: They belong to the order Crocodilia. One major difference is their salt tolerance. Crocodiles have special glands that help them excrete excess salt, so they’re comfortable in saltwater habitats such as coastal mangrove swamps. In alligators, those salt glands aren’t as well-developed, so gators are more likely to be found in freshwater.

Another difference is the shape of their heads. Crocodiles have longer V-shaped jaws, and alligator snouts are rounded and U-shaped. But there are exceptions; for example, the mugger crocodile of India and the surrounding region has a rounded snout like an alligator. Note that there are a couple of other members in the order Crocodilia that have EXTREMELY narrow snouts—the weird-looking false gharial and the even weirder-looking gharial.

Here’s another identification tip: take a look at the teeth. In crocodiles, the fourth tooth on the lower jaw sticks out, overlapping with the upper jaw and making the mouth look like a jigsaw puzzle gone horribly wrong.

7. LEOPARDS VS. JAGUARS

Leopard (left, Wikimedia Commons); Jaguar (right, Wikimedia Commons)

They’re both big cats, and they’re both speckled. But if you see a jaguar or leopard in the wild, it’s easy to figure out the species, because they live on separate continents. Leopards inhabit parts of Africa and Asia, and jaguars are found in South and Central America, as well as occasionally the southwestern United States.

Here are a few other ways to distinguish them. Both cats have clusters of dark spots on their fur, but jaguars have smaller spots inside each cluster. Leopards are also smaller and more slender than jaguars, and their tails are longer. You probably won’t need any of these tips, though, because these animals are notoriously secretive and hard to find.

What's the Difference Between Pigeons and Doves?

iStock
iStock

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

iStock
iStock

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.

A black kitten stretching
iStock

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.
iStock

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
iStock

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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