Today’s Wonder of the Day was inspired by Merrit from Coeur d Alene. Merrit Wonders, “What is a nudibranch?” Thanks for WONDERing with us, Merrit!

Has anyone ever told you that you are what you eat? Did you picture yourself as a pancake after breakfast or a big slice of pizza at dinnertime? What you eat affects your body, but you don't really turn into the food you eat! Unless, of course, you're a special animal called a nudibranch (NEW-dee-bronk).

Nudibranchs are sea slugs that live in the shallow waters of the oceans. Have you ever seen a snail making its way down the sidewalk? Nudibranchs look a lot like snails. The difference is that nudibranchs don't have shells. Instead, they have feathery gills and horns on their backs.

Are you WONDERing what nudibranchs look like? Well, that all depends on what they've been eating! Nudibranchs get their colors from the food they eat. That means that these sea slugs come in every color imaginable! They eat anything they can find on the ocean floor. That includes algae, sea sponges, and corals. It's rare for any two nudibranchs to look the same.

A nudibranch's color helps it blend in with its surroundings and escape from predators. A nudibranch that eats mainly coral will take on the colors of the coral to be able to blend in with a coral reef. When fish come swimming by searching for their lunch, the nudibranch blends in with its surroundings like a chameleon!

Color isn't the only thing nudibranchs get from their food. When they eat something poisonous, they can store the poison and use it for protection later. Nudibranchs have been observed eating toxic sea sponges and becoming toxic themselves. These toxins cause nudibranchs to turn bright shades of red, orange, and yellow, signaling to predators that they are poisonous and should not be eaten.

Nudibranchs come in many shapes and sizes. Fully grown, they can be anywhere from 0.25 to 12 inches long. While most nudibranchs are oblong in shape, their width varies widely. While some are a few inches thick, others are flat as pancakes. They also grow different numbers of tentacles depending on their needs. Each nudibranch looks unique!

Have you ever opened your eyes underwater? If you have, you know it's difficult to see! Nudibranchs have a hard time seeing under water, too. To find food, they have two sensitive tentacles on top of their heads. They feel out their prey with these tentacles when looking for something to eat.

If you were a nudibranch, what colors would you be? Would you be green like zucchini and green beans? Or would you turn red like apples and strawberries? How would you look similar to or different from your friends and family? If you are what you eat, then what are you?

Wonder What's Next?

Stand up and touch your toes before settling in with tomorrow's Wonder of the Day!