Crustaceans

Hello there. I am a crustacean, and I want to welcome you to my world. My family is one of the biggest and oldest on the entire planet. Our story began a very long time ago, way back in the Cambrian period. That was over 500 million years ago, when the first oceans were just beginning to fill up with all sorts of new and wonderful life. From the very beginning, the most important thing about me and my relatives has been our special protective covering. It’s called an exoskeleton, and it’s like I get to wear my very own custom-made suit of armor every single day. This strong outer shell keeps me safe as I explore my home, whether it’s a deep ocean trench, a sunny coral reef, or a quiet freshwater stream.

My exoskeleton is fantastic for keeping me safe from predators, but it has one little problem—it doesn’t stretch. Can you imagine wearing a suit of armor that never gets any bigger, even when you do? That’s the challenge I face. So, how do I grow? I have a special trick called molting, or ecdysis. When my shell gets too snug, I have to perform a tricky wiggle to slide right out of it, leaving the old, tight one behind. For a little while after I molt, my new shell is soft and squishy. This is a dangerous time for me, so I have to find a good hiding place and wait patiently for my new, bigger armor to harden. It might sound a bit strange, but this molting process is the only way I can get bigger, and it’s one of the most important cycles in my entire life.

My crustacean family is enormous. Scientists have counted over 67,000 different members, and we all come in different shapes and sizes. Some of my cousins are the tiny krill, so small that millions of them can fit together in a giant swarm, becoming food for the biggest whales in the sea. Then there are my giant relatives, like the Japanese spider crab, whose long, spindly legs can stretch wider than a car. Some of my family members are incredibly colorful, like the shrimp that dart around coral reefs, while others have even learned to live on land. If you’ve ever found a little pill bug, also known as a roly-poly, in your garden, you’ve met one of my land-dwelling cousins. It took a long time for people to understand our huge family tree. In the 1790s, scientists like Pierre André Latreille began the hard work of classifying all of us, helping everyone understand how we are all connected.

Being a crustacean isn't just about having a cool shell or lots of interesting relatives. We have very important jobs to do in our habitats. Many of us are like the official clean-up crew of the ocean. We scuttle along the bottom, eating leftover scraps and other things that fall to the seafloor. By doing this, we help keep the water and the environment tidy and healthy. We are also a key part of the food web. So many different animals rely on us for their meals, from fish and birds to seals and giant whales. By being both recyclers of nutrients and a source of food for others, we play a crucial role in keeping the entire ecosystem balanced. Without us, the underwater world would be a very different place.

Legacy & Remembering
Our story is still being written every single day, in every ocean, lake, and river on Earth. We are a living reminder of how life can adapt and find a way to thrive in almost any environment. From the freezing poles to warm tropical waters, you can find a member of my family. The next time you see a crab scurrying across the sand, a shrimp in a tank, or a crayfish in a stream, I hope you’ll remember our ancient history. Think of the important job we do and the big role we play in keeping our planet’s waters healthy for everyone.