- There are some 400 different species of mantis shrimp.
- Some grow up to 30 centimeters (11 inches) in length.
- Locomotion is via the usual shrimp and lobster method of using their swimmerets on the underside of the tail but the tail can also be used as a powerful swimming tool propelling them backwards and out of trouble.
- The last three pairs of thoracic appendages are used for walking.
- In some countries in the East they are regarded as delicacies.
- They are Stomatopods which are predators that feed on fish, mollusks, cnidarians, and other crustaceans.
- They use their powerful claws to smash the shells of their prey
- Some species live in burrows and ambush passing prey
- They have a highly sophisticated visual system and are highly evolved creatures.
- Their eyes are mounted on stalks and can move approximately 70 degrees in any direction.
- Visual information is processed in the eye itself before being transmitted to the brain, sort of like and advanced graphics processor in a computer.
- They can see both normal light and polarized light.
- Some species have up to 16 types of photo-receptors by comparison humans have 4.
- They have specialized color filters on their retina which further process visual information.
- The vision of some species begins in near-infrared, spans our entire visible spectrum, and goes across into ultraviolet light.
- At least one species is able to detect every known source of light both polarized and normal across the entire spectrum giving it optimal vision.
- The areas in which the mantis shrimp live are areas of extremely rapidly changing light conditions both during sunlight and moonlight, each tiny wavelet on the surface focusing surface light downwards in a multitude of different directions every millisecond creating a discotheque type environment of extremely rapid multidirectional light changes too fast for most eyes to deal with and see. In this environment the mantis shrimp with its eyesight reigns supreme out processing all other eyes.
SMASHERS AND SPEARERS
- They exploit the physics of cavitation and pack a punch way over their weight.
- There are two main types of mantis shrimp; smashers and spearers, dictated by the claw shape. Both types have specialized arms that use powerful muscles to pull back the claw which is then locked in place. Smashers physically hit the prey and spearers impale the prey on the claw.
- When released the speed of release is similar to a powerful spring being released and the appendage travels at such a speed that cavitation bubbles are formed, these then collapse, creating a powerful energy conversion which translates into a shock wave.
- The prey is hit by both the claw and the shock wave, creating a concentration of force. Even if the claw misses, the shockwave often does the trick.
- Normally this shock wave is used to stun, shock, smash or spear prey such as crabs or other crustaceans but can be used for protection.
- Some species can smash glass up to 10 mm (3/8″) thick.
- Some species are monogamous while others are not. The monogamous species can live together for up to 20 years.
- Some smaller species of mantis shrimp are free swimming and periodically swarm in their millions. It is not known what triggers these massive hatchings which tend to occur on an irregular basis.
- The species vary greatly in their behavior, but visual signals seem to exist between different individuals and some can fluoresce.
- In some species the female lays two sets of eggs one for the male to tend to, and the other for the female to tend to.
- Keeping stomatopods in aquariums has become a popular hobby among some marine aquarists who prefer the unusual.
A fantastic video about the mantis shrimp: