The crustacean which can punch through glass at the speed of a bullet: The Mantis Shrimp
Some cool stuff from blamoscience about the mantis shrimp:
Mantis shrimp, or stomatopods, are an ancient group of marine predators that are only distantly related to other more familiar crustaceans, such as crabs, shrimp and lobsters. Most occur in shallow tropical marine waters, but a few species are found in more temperate seas.Â
While they are called mantis shrimp, they are neither shrimp nor mantid (a species of insect), but received their name due to their resemblance to both praying mantis and shrimp. Mantis shrimp appear in a variety of colors, from shades of brown to bright neon colors.
More cool facts about the mantis shrimp:
- They can grow up to 38cm (15inches) in length…. which is longer than the big rulers at school!
-  Mantis shrimp are incredibly powerful and have been known to break right through aquarium glass by punching it with a single strike of its claw. That’s why in the aquarium I work in, the mantis shrimp sits behind incredibly strong and thick plastic which doesn’t smash like glass! Some species (smashers) smash their meals (mostly shellfish) apart with their claws, although they also have a sharp edge which cuts prey. They unfold their spring-like arms with astonishing speed, with an acceleration of 10,400 g (102,000 m/s2 or 335,000 ft/s2) and speeds of 23 m/s from a standing start. This is about the acceleration of a .22 calibre bullet. The force of the claw bludgeoning prey can reach up to 1500 newtons!
- Even if the mantis shrimp misses the prey, the prey are not so lucky… Inertial cavitation (where a bubble in a liquid collapses and produces a shockwave) in the surrounding water is caused by the speed of the mantis shrimp’s punch. It causes a huge shockwave which can stun or injure potential prey even if they are not touched by the shrimp! This also means that a mantis shrimp can hit their prey twice with a single strike!
- The claws of mantis shrimps wear down and thin very quickly due to the force of cavitation bubbles. In response to this, they shed their hard exoskeletons every three months and regenerate new, hard claws.
- Mantis shrimps have formidable eyesight; with 16 different types of photoreceptor pigments for colour sensitivity and colour filtering, their eyes are perceived as the most complex in the animal kingdom. They have hyperspectral vision (which is the ability to see many different colours from the light spectrum including all of those which we can see and more- such as UV light).
- Mantis shrimps have eyes on stalks which move independently of each other. The eyes of mantis shrimp may enable them to recognize different types of coral, prey species (which are often transparent or semi-transparent), or predators, such as barracuda, which have shimmering scales. Alternatively, the manner in which mantis shrimp hunt (very rapid movements of the claws) may require very accurate ranging information, which would require accurate depth perception.
- Mantis shrimp are long-lived and exhibit complex behaviour, such as ritualised fighting. Some species use fluorescent patterns on their bodies for signalling with their own and maybe even other species, expanding their range of behavioural signals. They can learn and remember well, and are able to recognise individual neighbours with whom they frequently interact. They can recognise them by visual signs and even by individual smell. Many have developed complex social behaviour to defend their space from rivals.
- In the monogamous species, the mantis shrimp remain with the same partner for up to 20 years. They share the same burrow and may be able to coordinate their activities. Both sexes often take care of the eggs (biparental care). In Pullosquilla and some species in Nannosquilla, the female will lay two clutches of eggs: one that the male tends and one that the female tends. In other species, the female will look after the eggs while the male hunts for both of them. Once the eggs hatch, the offspring may spend up to three months as plankton.
Now you know why they call them ‘thumb-splitters’ in Australia…. don’t mess with a guy who can punch at the speed of a bullet!
Image from http://www.richardherrmann.com/images_Showcase/11-L-mantis1.jpg.
