The peacock mantis shrimp – spectacular psychopaths

Photogenic little critters, aren’t they? Divided into two groups known as ‘spearers’ and ‘smashers’, these bizarre crustaceans sound a bit like two rival gangs in some budget spin-off of West Side Story. This may not be too far from the truth as peacock mantis shrimp (Odontodactylus scyllarus for anyone who cares) like to keep a bad boy image, sporadically attacking animals up to eight times their size. Whilst ‘spearers’ employ spiny appendages to grab and pierce through prey, ‘smashers’ go for a slightly less elegant approach and essentially bludgeon their prey to death.  They have evolved club like appendages that swing out at the same speed as a .22 calibre bullet (around 50mph). The fastest punch in the whole of the animal kingdom. This astonishing speed actually boils the water in front creating small bubbles, which upon rupture causes enormous force and pressure to be exerted upon the victim. This will often result in gruesome dismemberment – please see my diagram below for a 100% accurate visualisation.

(Click and zoom to enlarge)

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It is still unknown what horrors happen to these chaps in their childhood, but they have extreme psychopathic tendencies. It could be the fact that they can spend up to three months as plankton when hatched from the egg. No one really wants to be a plankton. They have been known to split human thumbs in half (probably deserved, which daft Doris is holding these creatures?) and even crack aquarium glass. Probably don’t pop anything in your tank with these guys either, they won’t be there for long (refer to above drawing). 

These Mike Tysons of the sea also have eyes amongst the most advanced and complex of all creatures, seeing twelve primary colours while we see an embarrassing three. Humans can only see colours derived from red, blue and green wavelengths. Mantis shrimp can see these plus seven other colours that we literally don’t even know about. In addition to this they can see normal, UV and polarised light. Basically imagine going on some sort of extreme acid trip whilst watching fireworks at a neon rave party, but with colours you can’t even think of. And that’s just the beginning. Humans have binocular vision; we can form an image with one eye but must use both to work out how far/close an image is (known as depth perception). Mantis shrimp have three eyes in one eye – trinocular vision per eye. This means they can see the world independently through each eye, giving an astonishingly wide field of view. 

There are many suggestions as to why mantis shrimp have this advanced vision (basically, we don’t have a clue). The strongest argument may be that they can easily discern between their own and other species, and have excellent depth perception for accurately attacking prey. One final thing that most people don’t know about the mantis shrimp (a.k.a it’s not on Wikipedia) is that their armour is so strong that current research is looking into how we could duplicate this strength for our own purposes. Fantastic to know we are still not as intelligent as the evolution of a psychotic clown.

References

Baldwin, J. & Johnsen, S. (2009). The importance of color in mate choice of the blue crab Callinectes sapidus. Journal of Experimental Biology212(22), 3762-3768.

Dingle, H. & Caldwell, R. L. (1969). The aggressive and territorial behaviour of the mantis shrimp Gonodactylus bredini Manning (Crustacea: Stomatopoda).Behaviour, 115-136.

Marshall, J., Cronin, T. W., Shashar, N., Land, M. (1999). Behavioural evidence for polarisation vision in stomatopods reveals a potential channel for communication. Current Biology9(14), 755-758.

Maynou, F., Abelló, P. & Sartor, P. (2004). A review of the fisheries biology of the mantis shrimp, Squilla mantis (L., 1758)(Stomatopoda, Squillidae) in the Mediterranean. Crustaceana, 1081-1099.

Patek, S. N. & Caldwell, R. L. (2005). Extreme impact and cavitation forces of a biological hammer: strike forces of the peacock mantis shrimp Odontodactylus scyllarus. Journal of Experimental Biology208(19), 3655-3664.

Patek, S. N., Korff, W. L. & Caldwell, R. L. (2004). Biomechanics: deadly strike mechanism of a mantis shrimp. Nature428(6985), 819-820.

Taylor, J. R. A. & Patek, S. N. (2010). Ritualized fighting and biological armor: the impact mechanics of the mantis shrimp’s telson. The Journal of Experimental Biology213(20), 3496-3504.

Weaver, J. C., Milliron, G. W., Miserez, A., Evans-Lutterodt, K., Herrera, S., Gallana, I., Kisailus, D. (2012). The stomatopod dactyl club: a formidable damage-tolerant biological hammer. Science336(6086), 1275-1280.

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3 Comments on “The peacock mantis shrimp – spectacular psychopaths

  1. You should do a natural sciences version of horrible histories! 11 year old boys would love this! Interesting and funny, well done mate!

  2. Pingback: The pink fairy armadillo – whimsical scufflers | WildlifeChat

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