Hermit crabs and sniffing!

I study how crabs sniff. Why is it important to understand how crabs sniff? Because sniffing is important to crabs! Imagine you are a crab in a bay looking for food. The water is very murky, you can barely see your claw in front of your face. How are you going to ever find that tasty dead fish? You sniff it out, of course!

Just like dogs, crabs use their noses to sniff out food and other crabs. But their noses look really different than a dog's. They have a little toothbrush-shaped thing called an antennule, and the bristles of the toothbrush are hairs that sense chemicals in the water. Crabs wave, or flick, this antennule back and forth, and when they do this, the hairs splay apart and catch a bit of water that sticks in between all the hairs. It's just like when you take a long sniff of something that smells good, it stays up in your nose for awhile until you breathe it out. So when crabs flick there antennules, they are taking a sniff!

Here's a video of a crab sniffing under a microscope:



We understand a lot about how crabs that live in water sniff, but hermit crabs that live on the land are a little different. Instead of having a toothbrush-shaped antennule, their hairs are very short and are lined up like shingles on a roof:



So, we've figured out that they sniff too, even though they live in air and not water. But what if you are a baby hermit crab the size of a sand grain?? Can you still sniff like grown-up crabs? I want to study how these baby hermit crabs use their antennules to find food and water, and that's one reason why I'm going to Moorea: to get baby hermit crabs!

Do you think baby hermit crabs sniff? If they don't, how do you think they find food and water like adult crabs?