It’s been a while, but I’ve gotten the itch to get back to writing here. Lets jump back in with a bang!
Last month. I finally got a hold of the species of mantis shrimp that many would consider the crown jewel of Stomatopoda – Odontodactylus scyllarus.
Personally I think O. scyllarus is a little too gaudy, completely without subtlety of appearance or demeanor; more of a painted tramp in my estimation. This particular animal is a female, as evidenced by the rusty carapace color. Males tend to be more green-ish.
This species is commonly referred to as a ‘Peacock Mantis Shrimp’ for obvious reasons; they are a riot of color. In addition to the color we can see, they also sport an impressive array of polarized signals around their bodies. They can make good use of these visual cues with sixteen spectral classes of photoreceptors and have been trained to discriminate color, linearly polarized light, and circularly polarized light.
O. scyllarus is also one of the largest true smashers, reaching over 7 inces in length. When you hear about mantis shrimp that can break aquarium glass, they are likely referring to this genus. They have been shown to generate strike forces with their calcified dactly hammers of up to 1500 Newtons, and can lash out at speeds of 20 meters per second.
O. scyllarus hails from the Indo-Pacific waters, and are found in slightly deeper waters, generally between 10 and 30 meters.
Finally, below is a video showing off the wild eye movements that this animal makes.
You’ll notice that each eye pans and rotates on multiple axes independently. They can do this and retain depth perception because each eye has independent range-finding capabilities. In order for optical range-finding you need at least two spatially separated visual fields observing the same point. We can use our two eyes together for binocular depth perception. Mantis shrimp on the other hand, have trinocular depth perception in each eye.
This is evidenced by looking at the pseudopupils. The pseudopupils are the areas of dark facets looking directly at the camera that seem to move around the compound eye of the mantis shrimp. You’ll notice that when an eye is looking directly at the camera, there are three spatially separated pseudopupils. Thus, by having three separate parts of each eye looking at the same point in space, mantis shrimp possess the capability for trinocular depth perception.
For information about aquarium care of this popular pet species, check out Roy Caldwell’s page.
- Marshall, J. et al., 1999. Behavioural evidence for polarisation vision in stomatopods reveals a potential channel for communication. Current Biology, 9(14), pp.755–758.
- Marshall, N.J., Jones, J.P. & Cronin, T.W., 1996. Behavioural evidence for colour vision in stomatopod crustaceans. Journal of Comparative Physiology A, 179(4).
- Chiou, T.-H. et al., 2008. Circular Polarization Vision in a Stomatopod Crustacean. Current Biology, 18(6), pp.429–434.
- Patek, S.N., Korff, W.L. & Caldwell, R.L., 2004. Biomechanics: deadly strike mechanism of a mantis shrimp. Nature, 428(6985), pp.819–820.