Thursday, 13 June 2013

Marvellous Mantis-shrimp

The mantis shrimp is one of the most unique organisms in the animal kingdom. It is a large crustacean that comes in a variety of different colours, from brown to neon. It is a ferocious predator and lives in tropical shallow waters1

One of the most unique features of this crustacean is the types of receptors in its eyes. Humans have 3 different types of colour receptors in the eye, allowing us to see a wide variety of colours. It has been suggested that in some humans there could be a fourth colour receptor, which is a variant and might play a role in heterozygous women (as it is on the X chromosome), allowing for a wider range of perception between colours and shades 2. However, the mantis shrimp has 16 different photoreceptors, 12 related to colour sensitivity and the remaining 4 involved colour filtering. This gives the mantis shrimp colour vision unparalleled in the animal kingdom. Allowing the mantis shrimp to see an incredible range of colours that humans could not conceive of, as well as other types of light, like polarised light and ultraviolet light. “Where we see a rainbow, the mantis shrimp sees a thermonuclear bomb of light and beauty”4.

Not only does the Mantis shrimp have amazing sight, but it is a ferocious predator with specially adapted appendages which can either spear or smash prey.  They are able to strike with this claw faster than a bullet, due to a mechanism of building up fourse and then suddently releasing it, causing the water molecules to boil and collapse and a shockwave is released5. This can stun the prey as well as producing cavitation bubbles which produce sonoluminescence, which is the release of light and extreme high temperatures for a few milliseconds6. The sheer force of the blow from a mantis shrimp means that is can smash through aquarium glass and is affectionately known as the ‘thumb splitter’ due to its ability to inflict considerable wounds to people who try to touch it7. Due to the extreme strength of the shell and claw the mantis shrimp is now being studied to help develop improved forms of body armour8