The mantis shrimp (Stomatopoda) is a marine crustacean found in the warm waters of the Indian and Pacific Oceans. Mantis shrimp pack powerful punches as strong as shotgun blasts.
Mantis shrimps typically grow to around 10cm in length. A few can reach up to 38cm. A mantis shrimp’s carapace covers only the rear part of the head and the first four segments of the thorax. Varieties range from shades of brown to vivid colors, as there are more than 450 species of mantis shrimp. They are among the most important predators in many shallow, tropical, and sub-tropical marine habitats. However, despite being common, they are poorly understood as many species spend most of their life tucked away in burrows and holes.
The mantis shrimp’s second pair of thoracic appendages has been adapted for powerful close-range combat with high modifications. The appendage differences divide mantis shrimp into two main types: those that hunt by impaling their prey with spear-like structures and those that smash prey with a powerful blow from a heavily mineralized appendage type club. A considerable amount of damage can be inflicted after impact with these robust, hammer-like claws. This club is further divided into three sub-regions: the impact region, the periodic region, and the striated region. Mantis shrimp are commonly separated into two distinct groups determined by the type of claw they possess.
While the advantage of sensitivity to polarization confers is unclear, however, polarization vision is used by other animals for signaling and secret communication that avoids the attention of predators. This mechanism could provide an evolutionary advantage, it only requires small changes to the cell in the eye and could be easily selected for. Research also shows their visual experience of colors is not very different from humans’. The eyes are actually a mechanism that operates at the level of individual cones and makes the brain more efficient. This system allows visual information to be preprocessed by the eyes instead of the brain, which would otherwise have to be larger to deal with the stream of raw data and thus require more time and energy.
While the eyes themselves are complex and not yet fully understood, the principle of the system appears to be simple. It is similar in function to the human eye but works in the opposite manner. In the human brain, the inferior temporal cortex has a huge amount of color-specific neurons which process visual impulses from the eyes to create colorful experiences. The mantis shrimp instead uses the different types of photoreceptors in its eyes to perform the same function as the human brain neurons, resulting in a hardwired and more efficient system for an animal that requires rapid color identification. Humans have fewer types of photoreceptors, but more color-tuned neurons, while mantis shrimps appear to have fewer color neurons and more classes of photoreceptors.
In Japanese cuisine, the mantis shrimp species Oratosquilla oratoria, called shako, is eaten boiled as a sushi topping, and occasionally, raw as sashimi.