Eyes, ears, mouth and nose

[snickersnflip]

as the title suggests, I have a bunch if random questions about Hermit crab's senses and stuff.

1.) do hermit crabs Hear? If so, do hey have like, a little ear hole or something? If not, do they have any sense of sound eg feeling vibrations, or anything like that?

2.) I know hermit crabs smell with the shorter anntinae (right?). How does that work? Do different species of hermies have better or worse senses of smell?

3.) are hermit crab's eyes compound, like a fly or ant's eyes? (It would be so weird to see through compound eyes LOL you could see behind and infront and all around you at the same time, i would be so confused!)

4.) i guess I don't really have a "scentific question" per say about thier mouth LOL But, how does one explain mouthparts to a child. LOL the other day my little sister walked up to the tank, ready to take a picture, and said "Smile crabs!" It was so cute. My neice like to ask questions a lot too. I'm just waiting for "how does he eat if he doesn't have any teeth?" Or something like that.

[Leeko]

As a caveat, I'm not really an expert in crustaceans or hermit crabs in particular, just a biology student, so I'm just applying my general knowledge here.

1.) do hermit crabs Hear? If so, do hey have like, a little ear hole or something? If not, do they have any sense of sound eg feeling vibrations, or anything like that?

I... have no idea. My instincts say no, not really, but they chirp occasionally so yeah I don't really know.

2.) I know hermit crabs smell with the shorter anntinae (right?). How does that work? Do different species of hermies have better or worse senses of smell?

I don't know about differences between species, but smell/taste are basically the same sense, and using those words when talking about invertebrates is slightly misleading. It's all chemical detection - in our case, our nose has detectors for airborne particles and our mouth has detectors that work on contact. If you've watched your crabs for any amount of time you've probably seen them rapidly waving their antennae up and down. They are (presumably) tasting the air. Teeny tastable molecules are drifting through the air all the time, like the ones that end up in your nose. You may have also noticed them touching things (food especially) with their antennae, as if to taste; that's exactly what they are doing.

3.) are hermit crab's eyes compound, like a fly or ant's eyes? (It would be so weird to see through compound eyes LOL you could see behind and infront and all around you at the same time, i would be so confused!)

Yup. As far as I know, arthropods (insects, crustaceans, arachnids, etc.) all have compound eyes.

4.) i guess I don't really have a "scentific question" per say about thier mouth LOL But, how does one explain mouthparts to a child. LOL the other day my little sister walked up to the tank, ready to take a picture, and said "Smile crabs!" It was so cute. My neice like to ask questions a lot too. I'm just waiting for "how does he eat if he doesn't have any teeth?" Or something like that.

I don't really know anything relevant. They break off and eat very very small pieces of food at a time, whereas we break off huge chunks and chew them down to a mushy paste.

[Rocky]

1) They don't "hear" per say, I believe they feel vibrations in the ground and in the air with their bodies and antennae, they're VERY sensitive!
2) I think it works similarly to snakes, they taste the air? I'm not too sure on that one, but I do know that they're sensitive enough to tell the difference between salt and fresh water at a distance
3) I don't believe they're compound or anything like a bug, but they only see in a certain spectrum that has yellows and greys and such
4) Their mouthparts are a bit weird, they have the claws to break down food, then a tiny pair of arms by their mouths to pick up the broken down food, and carry it to their mouths. Their mouths are mandibles, like most bugs Imagine a little pair of arms that carries food to a little mouth like a beetles or something

[kuza]

They make a sound when they grab onto each other, so I don't see why they can't also hear or that sound woudl be useless. We hear them "talking" before a mass molt ending, soo we must assume they can hear.

And Their antenna work just like a nose, it picks up minute particles in the air and sends the signal down to the brain.

[snickersnflip]

thanks guys! I guess i never really thought of them "tasting the air" before. I know snakes do that, but never thought of hermies doing it.

so they can only see certain colors? I never thought of that. Poor little dudes, they live in such a pretty environment in the wild (beach, jungley stuff etc) and they cant even see all the colors!

[Leeko]

3) I don't believe they're compound or anything like a bug, but they only see in a certain spectrum that has yellows and greys and such

They totally 100% definitely have compound eyes. All arthropods do.

[Rocky]

Ah, I'm no expert Thanks!