What’s the Difference?

by James Morris

What’s the difference between a …

Frog and Toad?

A toad is a type of frog. So, all toads are frogs, but not all frogs are toads. Frogs and toads both belong to a group of animals called Anura (from the Greek “without tail” because frogs are tailless). What we typically call frogs live in water; toads live on land, but near water. The skin of frogs is wet and smooth, while the skin of toads is dry and bumpy. Finally, frogs have teeth, but toads don’t. In total, there are about 7,000 species of frogs (frogs + toads), of which about 500 are true toads.

So, this is not unlike an …

Ape and Human

Humans are a type of ape. So, all humans are apes, but not all apes are humans. Apes are generally divided into two groups – Lesser Apes and Great Apes. Humans are Great Apes, a group that also includes chimpanzees, bonobos, gorillas, and orangutans.

The same goes for a …

Pupa and Chrysalis

A chrysalis is a type of pupa. Specifically, a chrysalis is the pupa of a butterfly or moth.

and a …

Larva and Maggot

A maggot is a type of larva. That is, a maggot is the larva of a fly.

Since we are on the topic of the young of organisms, what’s the difference between a …

Sheep and Lamb?

A lamb is a young sheep, just like a kitten is a young cat, a calf is a young cow, a cub is a young bear, and foal is a young horse.

But then what about a …

Horse and Pony?

A pony is not a young horse. A pony is a small horse, but can be any age.

or a …

Horse and Zebra?

A zebra is a type of horse, sort of like a toad is a type of frog. In fact, zebras and horses are so closely related that they can interbreed to produce zorses and hebras (really).

Similar to a …

Turtle and Tortoise

A tortoise is a type of turtle. Tortoises live on land, while what we think of as turtles live in many different habitats, including the water (think sea turtle). Tortoises are herbivores, while turtles are omnivores.

Which brings us to …

Catmint and Catnip

These are two different species of plants: catmint is Nepeta mussinii and catnip is Nepeta cataria. Catmint is more ornamental with purple flowers, while catnip looks weedier and has white flowers. As their names suggest, cats love them both, but only catnip makes them go crazy. Cats do show an interest in catmint, and tend to roll around in it (to the dismay of many gardeners, including me).

This is sort of like…

Hares and Rabbits

Hares and rabbits are two different groups of mammals. Hares are larger than rabbits, and the fur of hares can change color with the seasons (!).

Just like …

Alligators and Crocodiles

These are two different groups of closely related reptiles. Alligators tend to live in freshwater, while crocodiles prefer salt water. The snout of alligators is rounder, while the snout of crocodiles is more pointed. And, when they close their mouths, you can’t see the teeth of alligators, but you can see the teeth of crocodiles sticking up and down.

Then what about …

Dolphins and Porpoises?

These are two different groups of marine mammals, with a variety of distinguishing features. Most notably, dolphins are talkative and have a pointed snout, whereas porpoises don’t have a “beak” and don’t vocalize as much. Interestingly, orcas (or killer whales) aren’t whales, but in fact dolphins (but that’s the topic of another post).

But then what’s the difference between a …

Hominin and Hominid?

There isn’t. What used to be called a hominid is now called a hominin. Hominins include all of us, as well as our extinct human relatives, such as members of the groups Homo, Australopithecus, and Ardipithecus. Today, the term “hominid” is used for all members of the Great Apes.

And what’s the difference between a ….

Possum and Opossum?

There isn’t. In the US, these are the same animal. Some people call them possums, and some opossums. They are the only North American marsupial (that is, a mammal with a pouch, like kangaroos and koalas). Opossums have a white face, a bare tail like a rat, and sharp teeth.

but …

This gets confusing because, in Australia, a possum is a completely different animal from the North American possum/opossum. It’s also a marsupial, but the similarities end there.

So, what’s the difference? While numerous lists can be found online of the differences between these and other organisms, context often matters.

Take the red-tailed hawk and red-shouldered hawk. If you are in the Boston area and see a hawk, 9 times out of 10, it’s the red-tailed, not the red-shouldered. If you are on land in the Galápagos Islands, it’s a tortoise, but if you are in a boat offshore, it’s a turtle. And if you are in the Florida Everglades, you are more likely to come across an alligator and not a crocodile, even though they both live there. In other words, you don’t need to even think about these differences in certain habitats.

But, if you are in Australia, don’t say opossum. In fact, if all of these names make you feel like giving up and “playing possum,” you should know that, wherever you are, it’s always safe to just say possum.


© James Morris and Science Whys, 2019

Special thanks to Maya Fields, Devin Feigelson, and Moshe Levenson for helping me to come up with these colorful examples.

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