The world is full of a wide array of organisms from fish to frogs and from caterpillars to crows. Most of the time we can rely on our knowledge and intuition to loosely identify something that we see in the wild. It’s pretty easy to distinguish a worm from the cardinal getting ready to eat it. Other times, we don’t know what we’re looking at. Or maybe we think we know what we’re looking at, but science tells us it is something else. Here are a few living things that may not be what you think they are!
#1 Lightning Bugs (or Fireflies)
Occasionally, I think back to the long summer nights of my childhood. The weather was warm, and the days were long. Just as the sun started to disappear at the edge of the Earth, lights would start flickering off and on in the woods behind my house. My sister and I would throw on a pair of shoes and run outside to try to catch lightning bugs. In hindsight, I think it might have been a little mean to the insects. But that’s not what we’re here to discuss!

I never really thought about what lightning bugs were as a kid (other than some type of insect), so was I sure surprised to learn these glowing creatures are a type of beetle! There are over 2,000 different types of lightning bugs found throughout the world. They are distinguished from other beetles by their ability to glow in the dark (also known as bioluminescence).
Bioluminescence occurs because of a chemical reaction inside the firefly that produces its characteristic glow. Individual lightning bugs use this light to signal potential mates. Instead of buying the latest fashions to attract a mate, they perform an intricate light dance.
And, for the record, there is no difference between lightning bugs and fireflies. People just have different names for the same thing. Good thing too. Lightning beetle just doesn’t have the same ring to it.
#2 Seaweeds

Whether you eat it in your sushi or give a small shout when it brushes your foot in the ocean, chances are you’ve encountered seaweed before. Have you ever thought about exactly what seaweed is though? You may think that it’s a plant. After all, it’s green like a lot of plants. It also looks an awful lot like a plant. Depending on which website you click on the internet, it might even tell you that it IS a plant. TLDR: it’s not a plant.
Seaweed is actually a plant-like organism called algae. What is algae? That’s a good question. Most scientists categorize algae with protists – a group of eukaryotic organisms that are neither plants nor animals. However, science is always evolving. As we learn more information, classifications can shift or specialize. What we do know is that underwater plants (like seagrass for example) differ from algae in one key way: they have roots that anchor them to the ocean floor. Algae don’t have that. Instead, macroscopic algae (the stuff big enough for us to see with our naked eye) have a holdfast that helps them attach to rocks and other things. Microscopic algae (the ones that we can’t see with just our eye) just float around in the water.
So next time you feel something slimy touch your leg in the water – take a look at it. It could be seaweed. Or just run screaming out of the water. That works too.
#3 Corals
Take a look at the picture of the coral reef. Can you tell what parts of the reef are made up of corals? A lot of people know what a coral reef is, or they are familiar with the idea of one from a very popular Disney movie and its sequel (here’s a hint: just keep swimming, just keep swimming, swimming, swimming…). However, even if you know that a coral exists, you might not know exactly what it IS. Are corals just colored rocks? Maybe they’re a type of moss that grows over the ocean floor?

School biology classes taught us about the difference between plants and animals and prokaryotes (AKA bacteria) and eukaryotes (plants, animals, etc.). Just based on looks alone, corals don’t really seem to fit into any of those categories. So, what exactly are they? Corals are animals. Yep – you read that right. Those things that look like rocks or ferns depending on the species are living, breathing, eating animals. How is that possible?

One of the key things that makes an animal an animal is how it gets food. Animals are heterotrophs which means they can’t produce their own food (unlike plants that can produce food from the sun’s energy). Instead, they must collect it from their environment. For example, a bear eats berries and fish for food.
Corals get food two ways. First, they have small polyps all over their body that grabs at food particles as they float by. Second, corals rely on tiny algae (yep, those things again) that live inside them to produce their energy. This trait (along with a few others, but this is the important one) makes a coral an animal. They’re just strange looking ones.
#4 Beavers
Beavers are other organisms that I never really tried to classify as a kid. They were animals, and that was good enough for me. However, while scrolling through Disney+ the other day, Chronicles of Narnia came up on the screen. That’s when I remembered the beavers. “What exactly are beavers?”, I thought. I tried to pull the answer from the depths of my brain hoping to pull the tidbit from an old biology course. However, I quickly gave in and grabbed my smartphone.

Much to my chagrin, Google reminded me that beavers are rodents. My reaction only makes sense once you find out that I am absolutely, positively terrified of rats – and most other rodents by mere association. But beavers are cute. They couldn’t possibly be a rodent?
But, alas, they are. What makes a rodent a rodent? It’s their teeth that are specifically designed to gnaw on food. Animals such as squirrels, capybaras (the world’s largest rodent), and porcupines are all categorized as rodents. Here’s a fun fact for you: the word “rodent” comes from the Latin word rodere which means “to gnaw.”
#5 Whale Sharks

Now here is an animal that confused me a lot as a kid. I could never remember if a whale shark was a shark that resembled a whale or if it was a whale that resembled a shark. Try saying that five times fast.
Whale sharks are, in fact, sharks. They’re also the largest living fish on Earth (yep – sharks are fish). We don’t know exactly how big they can get. After all, we can’t just place them on the scale at the vet’s office. Most scientists agree they can reach about 40 feet long or just about the size of the school bus. Although, I have seen some reports that they can reach up to 60 feet. Either way, they are very big.
If you ever encounter a whale shark in the wild, don’t worry about them chomping down on your leg. These gigantic fish only eat plankton and other small creatures that get caught in their gills. They do have teeth, but most scientists agree that these are vestigial structures that aren’t used anymore.

Also – if you do see a whale shark – please don’t bother it. Maintain your distance and snap a few photos if you can. Otherwise, let it go on its merry way.
So there you have it…five organisms that aren’t what you think they are. Did any of them surprise you?