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Michael: There are lots of things in nature that we’ve given pretty odd names. Like, I know you know that seahorses aren’t mammals that gallop through fields, and sea cucumbers aren’t vegetables. The frickin’ strange geoduck? It can’t even pretend to be a bird. And the mountain chicken, it turns out, is actually a huge frog.

But a lot of the time, we give animals certain names, because they look or act a lot like another kind of animal … so much so that we can’t really tell the difference between the two. Picking common and scientific names is a puzzle of taxonomy, the science of classifying organisms based on their biological traits and evolutionary history.

A lot of what we think we know about the animal kingdom can be understood through what we call things... And why they aren’t necessarily what they appear to be. So here are 7 animals that aren’t what we call them.

[1. Jackrabbits] To start us off, we have the lanky, long-eared jackrabbits, which are actually not rabbits. They’re hares. The name “jackrabbit” is used to describe six different species of hares that live in middle and western North America. Their name supposedly comes from settlers who said they looked like rabbits with donkey ears – so, a “jackass-rabbit.”

But jackrabbits and true rabbits are more like cousins. They’re both in the family known as Leporidae, and are generally called leporids. But that family contains 11 genera, most of which are rabbits. Only one is for true hares, the genus known as Lepus.

So, what’s the difference? Well, both rabbits and hares have skulls with bony bumps that define their eye sockets, and teeth that grow constantly, kind of like rodents' do. Plus, they both have two huge front teeth covered in enamel, with two tiny teeth right behind them. And they do look similar: y’know, short bushy tails, long ears, big hind legs, and big feet.

But here’s the thing: some of these similarities might be partially because of convergent evolution. Over the past 12 to 16 million years, scientists think some of their similar traits developed separately in different species of rabbits and hares, rather than coming from a common ancestor. Eventually, researchers realized that jackrabbits are true hares, which ended up being an important distinction.

Hares are more solitary animals than rabbits, for example. They don’t build burrows or live in colonies, and they have different survival adaptations, like taller ears and longer legs to detect predators and run away. Also, hares don’t reproduce like rabbits. Unlike rabbits, who have protected burrows, female hares give birth wherever they feel like it, out in the open, to babies who are born with full coats of fur and can start moving right away.

[2. Mountain Goats] Next up are the woolly white mountain goats, which – you guessed it! – aren’t goats! They’re in the same subfamily as goats, known as Caprinae, which includes critters generally called caprids. But true goats are in the genus Capra, while mountain goats are the lone species in Oreamnos.

All caprids are kind of stocky, and have hooves that are built for rough terrain, with foot pads and stubby dewclaws that can help some of them grip rocks. And they’re sexually dimorphic, so males usually have bigger bodies and bigger horns than the females. But mountain goats are physically different from true goats. They have short, black, pointy horns, and white fur.

In the winter, their fur is shaggier to help them stay warm, but they shed it for a shorter coat in the spring. And mountain goats only live in western North America, in mountain ranges like the Rockies and the Cascades – which is how they got their common name. But this is also why we don’t know very much about the evolution of mountain goats: It turns out that rocky mountains aren’t great for preserving fossils, so the natural history of these not-goats is largely unknown.

[3. Mountain Lions] Then, we have the not-quite king-of-the-jungle, the mountain lion, which isn’t actually a lion. Mountain lions go by a lot of common names, like cougars, pumas, panthers, and catamounts.

And all cats are members of the family Felidae, but mountain lions are in the Puma genus, while the two subspecies of true lions are in Panthera. Felids are specialized, carnivorous hunters, which diverged from the now-extinct saber-toothed cats. They all have similar muzzle structures, cone-shaped teeth, and tongues with spiky papillae to help clean themselves and remove all that meaty goodness from their prey. Plus, they have five toes on their front paws, and four in the back – and retractable claws.

But mountain lions only live in the Americas, while true lions prowl around Asia and Africa. And cougars are also a lot smaller than lions, and they prefer a solitary lifestyle rather than traveling in prides. They’re also sexually dimorphic, but cougar males are just slightly bulkier than the females, while male lions have that iconic mane. And they have different skull structures -- specifically, near the hyoid bone, which sits at the back of their tongue, and the larynx, which is the organ that helps them make sounds.

Lions have stretchier vocal tissues, and a less-solid hyoid bone, which is why true lions can roar. Mountain lions, on the other hand, have more solid hyoid bone and different tissues that makes them purr instead – just like our kitty companions.

[4. Flying Lemurs] Flying lemurs might remind you a little of King Julien from the Madagascar movies, but it turns out, they’re not even in the same order as lemurs. Lemurs are Primates, while flying lemurs, also known as colugos, belong to the order known as Dermoptera. And they live in totally different parts of the world. Colugos mainly live on islands in Southeast Asia, like Borneo, Java, and the Philippines – whereas true lemurs are native to Madagascar and its nearby islands.

The easiest way to tell them apart? Colugos glide, with the help of a membrane called a patagium that stretches between their chin, limbs, and tail. So, even though they’re in different parts of the mammal family tree, scientists do know that primates and flying lemurs are taxonomically related, along with the order that contains tree shrews. But they’re still trying to figure out how they’re related. Right now, it’s mostly a mystery.

[5. King Cobras] But enough about mammals! How about a reptile? Take the king cobra. It’s not actually the head of a snake monarchy... and it’s not a cobra, either. King cobras are alone in the genus Ophiophagus, and not Naja like the true cobras. But they’re all in the family Elapidae.

True cobras roam on land and in water across Africa, the Middle East, and parts of Asia, while king cobras tend to hang out in India and Southeast Asia. All these snakes have short fangs on their upper jaw, and you probably don’t want to get too close to any of them. Their venom is generally a fun mix of neurotoxins, which means it can mess up your nervous system, and cytotoxins, which means it can damage cells and tissues directly.

Now, this name mix-up is also pretty understandable, since “cobra” comes from a Portuguese phrase for “snake with a hood.” In both types of snakes, the hood is actually made of rib bones that the snakes can flare out using specialized muscles – to look all scary as a first line of defense. But physically, the king cobra has a narrower hood than true cobras, and it has a chevron pattern on it, instead of the characteristic design that looks like freaky eyes staring at you.

The king cobra is also the longest of the venomous snakes. Plus, it's evolved different methods to regulate its venom secretion – so it injects more of a highly potent toxin than true cobras do, to kill its prey. And finally, in addition to eating small vertebrates like mice like its cousins do, the king cobra also straight-up eats other snakes. To which I say, well played.

[6. Electric Eels] Let’s dive underwater for our next misnomer: electric eels. But, prepare to be disappointed, because they’re not actually eels, they are knifefish. Knifefish and eels are both bony fish with ray-fins, which have thin bones and less muscle. But electric eels are actually in the order Gymnotiformes, rather than true eels, which are in Anguilliformes.

Most eels live in saltwater, although some live most of their lives in freshwater, and return to the ocean to breed. So when someone discovered the long, tubular electric knifefish in the muddy rivers of South America, they probably just assumed it was an eel. Upon closer inspection, though, electric eels only have a big fin on the bottom – and lack the dorsal one that true eels have.

True eels can also get oxygen through their skin and gills. But electric eels live in such low-oxygen waters that their gills aren’t always enough. In those muddy rivers, they have to pop up to the surface to breathe air, using vascular tissues in the lining of their mouths that absorb oxygen, kind of like our lung tissue does.

And most notably, electric eels are, electric. They have special organs that can generate shocks up to 600 volts, enough to give a significant jolt to a human, or snag some prey for dinner. That’s what puts electric eels in the ranks of knifefish, because all knifefish can generate weak electric fields using similar organs. They use these fields to tell what’s nearby, like food, predators, or other electric fish. And knifefish can even use them to talk to each other.

[7. Mantis Shrimp] We’ll end with the super-weird super-tough mantis shrimp. As you can probably guess, they’re not shrimp, or even in the same order as them. They’re a type of crustacean, in the huge class Malacostraca, which contains tens of thousands of diverse creatures.

Mantis shrimp, or stomatopods, are in the order Stomatopoda, rather than Decapoda like lobsters, crabs, and shrimp. They all have a hard, segmented exoskeleton, but have different specialized limbs and body parts that help them feed and fight. So it’s possible that the mantis shrimp got its name because it looks like a small-ish crustacean with bulging round eyes and antennae-like structures around its face.

But stomatopods diverged from crustaceans over 250 million years ago, and evolved into ridiculous predators. Shrimp are omnivorous and scavenge whatever they can find, but mantis shrimp are stone-cold killers. They have two types of highly specialized claws: spiny ones that can stab prey, and others designed like hammers that can punch at speeds around 80 kilometers per hour.

So what’s really in a name? When it comes to animals, it’s a lot of guesswork, and sometimes we just totally get things wrong. But, hey. Scientists are always figuring out how to classify and reclassify species. So really, calling an electric knifefish an electric eel isn’t going to hurt anyone. And if you find yourself cornered by a bunch of king cobras... is it really going to matter what order it belongs to?

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