More on Mole Crabs

Thanks for all of the comments about mole crabs! My students and I enjoyed reading the comments. Several of you had some great questions about the little crabs. Here are some answers.

How big do they get?
The mole crabs that we find at the beach (Ocean City, Maryland or Assateague) are usually 1.5 inches or less. You can see Zachary holding one in the picture. That's one of the bigger ones that we found. The smaller ones are about .5 inches.

Can they live in Lake Erie?
I don't think so. It's my understanding that they are saltwater creatures. Lake Erie, as you know, is freshwater. But I'd love to research and find out more.


Can mole crabs be different colors? 
Life is tough if you are a tiny (and delicious) little crab. Why do you think that mole crabs are the color that they are? Where might you find mole crabs that have different colors?

Why do mole crabs stay in wet sand?

Good question! The mole crabs are filter feeders. They stay close to the waves because they put their antennae up to feed when a wave comes by. Because this is how they eat, they like to stay in the wet sand.

Why are they called mole crabs?
When I started researching them, I was actually surprised to find that this is their most well-known name. We always called them "sand crabs" when I was growing up.

But the name makes sense. If you happen to be at the beach while they are digging down into the sand, they do look like moles digging into the ground. Moles dig, and these crabs dig, so the name fits!

A Special Vernal Pool

A vernal pool is a pool that is wet through the spring, but dries up in the summer. Vernal pools are special habitats. They can be homes to wood frogs, spotted salamanders, and fairy shrimp.

On the last weekend in May, I found an interesting new vernal pool! Can you tell what has happened? The old tree fell over, probably during the winter. In the hole that was left behind, a vernal pool has formed. This pool is nice and shady, perfect for small creatures.

But had any creatures come to this vernal pool? I poked around a bit to find out. There, in the middle of the pool, I saw a baseball-shaped blob of eggs! Salamander or wood frog? They were a little too far away to tell--and I didn't want to reach into the pool to find out.

What was so neat is that this vernal pool had not been here last year. It's brand-new! It just shows how things in the forest are always changing--and when one thing goes away, like the old oak tree, something new can take its place.