The eyes of a clam!

[calvertbill]

I have six clams, a Maxima, 3 deRasas, and 2 crocea.
The 2 crocea and occasionally the Maxima will suddenly close when I approach to look at them.
I started out with the assumption that clams are eyeless so it must be a great sensitivity to the vibration of my footfalls transmitted through the floorboards, through the tank stand, through 450 gallons of water.
Only thing is, they'll sometimes close if I just shift in my chair to get a better camera angle!
Howdeydodat?

 

[anadliv]

not sure what the technical name is for the cells in the mantle but they are highly resposive to changes in light

 

[paintballer768]

Photoreceptors on the mantle. All over the room if I move, it usually will response. I think movements can have something to do with it though.

 

[jrthomas40]

i dont think it is eyes but photorecepters and they react to quick movements or quick changes in light intensity...hence when you wave your hand in front of the light casting a shadow over the clam it will flinch

 

[viper_930]

Tridacna clams do in fact have eyes, but not eyes like us or a fish to see a picture. Sometimes a single clam will have a couple thousand eyes. They can detect changes in light, colors, and also movement. The eyes can look like small black dots, often around the edges of the mantle. IME with croceas and maximas the eyes can protrude and look like a small bump.

 

[babyb]

thats amazing, i never knew that