The Mantis shrimp is a very colourful character indeed. I think along with nudibranchs, which I hope to get round to soon, they are some of the most visually stunning creatures in the sea. Mantis shrimp are mostly found in the tropical seas of the Indian and Pacific oceans, but there are a few temperate sea species as well. At around 10 cm (4 in) long, the biggest species grow up to 38 cm (15 in) with the largest caught reaching 46 cm (18 in). The mantis shrimp can be found among rock formations or sometimes in sea bed burrows. Nannosquilla decemspinosa lives in tidal pools and if caught out of one when the tide recedes it can be stranded as its legs are very short. To solve this problem it will somersault forward and try to roll like a wheel to the nearest pool.
By Ed Bierman from CA, usa (Mantis Shrimp with Nudibranch) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons
Some species, like the peacock mantis shrimp Odontodactylus scyllarus, display an astonishing array of patterns and colours and this can be used in communication. Others have been observed recognising those they have common interactions with, some through visual signals and others through chemical cues. Polygamous and monogamous relationships occur across mantis shrimp species with some sticking with their partners for up to twenty years.
By Jenny (originally posted to Flickr as mantis shrimp) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons
Mantis shrimp can be separated into two categories, smashers and spearers. As you have probably gathered, the spearers have appendages with barbed spines that are more adapted for softer prey, such as fish, while the smashers use their appendages to club their victims. This allows them to hunt harder prey like gastropods. Now comes the really cool part. Striking with a speed of 23 m/s, the force at which they can hit their prey is estimated at around 1,500 N, which is almost the force of a cougar bite. And it gets cooler. If the claws miss then the shockwave from the collapsing cavitation bubble that is created by the acceleration of the claws (104,000 m/s2) can stun or kill. And there’s more. When this bubble collapses, at its centre the temperature can exceed the surface temperature of the sun, and it produces light! This is called sonoluminescence.
By Roy L. Caldwell, Department of Integrative Biology, University of California, Berkeley.Chhe at en.wikipedia [Public domain], from Wikimedia Commons
Not content with what it has so far, the mantis shrimp also possess one of the most complex eyes discovered in the animal kingdom. Each eye is attached to a separate stalk which can move independently of the other, and is divided into two hemispheres with six rows of ommatidia. Ommatidia are the units which make up the compound eyes found in arthropods. This set-up allows the mantis shrimp to perceive polarised and ultraviolet light. This also gives them trinocular vision, allowing depth perception, and while humans have three colour receptors, they have sixteen. Kinda ruins rainbows a little when you think what the mantis shrimp must be seeing.
By Nazir Amin (Mantis Shrimp) [CC BY-SA 2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons
If you enjoyed that post, I would suggest reading up a little about the snapping shrimp, which use their claws in similar ways and have been known to make noise that can compete with whales! If you like my posts I would love to hear your opinion. I’ll leave you with this video and some more awesome mantis shrimp pictures since, let’s face it, they look awesome.