The awesome abilities of the peacock mantis shrimp surpass even its vibrant looks, which is saying a lot.
The only thing more devastating than the mantis shrimp’s vibrant look is its punch.
Australia has an infamous reputation as being home to some of the world’s deadliest creatures. Whether that is fair or not, I will explore some of Australia’s most fearsome creatures from the country’s past and present in the Deadly Australia segment.
When thinking of the ocean’s most efficient predators, the mantis shrimp would probably not be the first thing to come to mind. Most species are small, live along the ocean floor, and only hunt small fish and crustaceans. The first thing you would notice if you came across a mantis shrimp scuttling about would be the brilliant jumble of colors that make mantis shrimp vividly pop out against their sandy backdrop. But beneath the bright exterior, the mantis shrimp possesses superpowers well beyond what we envision in comic books and uses those powers to become the most lethal hunter on the seafloor. It is a wolf hiding in bright peacock plumage; a calculated assassin masquerading as a harmless tie-dyed jester scuttling on the sand.
It is not often for shrimp (mantis shrimp are actually relatives of shrimp called stomatopods) to become relatively well known to those outside the realm of marine biology unless they’re fried and on a plate. The mantis shrimp, however, has multiple jaw-dropping biological traits that have made it one of the most interesting creatures on the planet.
First we should start with the eyes. Peacock mantis shrimp (Odontodactylus scyllarus) have the most specialized eyes of any animal on the planet, maybe any animal to ever live. They have compound eyes, like other crustaceans and insects. One of the reasons the eyes of the mantis shrimp are so incredible is because each eye has three parts that could each work as an eye by themselves. The eyes consist of two parts (practically two different eyes) above and below a belt-like structure that splits each eye across the middle. This third part of the eye is aptly called the “midband.” Humans need both of our eyes to focus and locate an object while a mantis shrimp can do that with only one eye.
The remarkable design of these eyes allow mantis shrimp to see things we cannot even comprehend. Humans can see three primary colors because we have three types of color-receptive cone cells, green, blue and red. All the colors we perceive in the world are based off of these three colors. The sense of color of a mantis shrimp blows our paltry three color system out of the water.
They have 12 different primary color sensors, meaning they can see the three colors we can, but also have 9 other visible colors that we cannot even comprehend. Our rainbow is made up of the three colors we can see (with some variation between those colors, like purple or orange). The rainbow available to mantis shrimp eyes would be an incredible psychadelic explosion of colors from the deepest ultraviolet to colors with wavelengths far higher than we can see. However a study done by the University of Queensland found that mantis shrimps are actually worse at detecting slight color variations than humans are. That means that mantis shrimp aren’t concerned with small color differences because they must not be important for hunting.
They can also see ultraviolet light, which is invisible to humans. The shrimp’s specialized midbands can help separate this electromagnetic light into different colors. The midband also allows the shrimp to see the polarization of light, something our eyes, again, cannot come close to replicating on our own. Mantis shrimp can see light waves vibrate, a trait along with its extreme visual color-pallette and ability to see ultraviolet colors, makes it the best equipped visual predator on the planet. The information the shrimp’s eyes perceive is shot right to their brains so they can quickly digest the data and strike prey even quicker.
Their lightning-quick punch is so powerful it can boil the water around them and kill prey even if it manages to miss them. The mantis shrimp has two fist-like appendages called raptorial appendages, which look something like the front legs of praying mantis, its namesake. Behind these clubs are muscles that are capable of extending completely out in hundredths of a second, which makes the clubs spring from the shrimp’s body at 50 mph and accelerate faster than a .22 caliber bullet. When these clubs hit their target they can deliver 160 pounds of force.
Even if the shrimp misses, its target is still in hot water. Literally. Because their appendages shoot out so fast, the water around them is heated and boiled through the process of supercavitation. The ensuing boiling bubbles can burst and create shockwaves that can stun or kill the prey the shrimp missed. The shrimp then dismembers its prey by smashing it to pieces. Mantis shrimp are rarely kept in aquariums because their punch is so powerful it can shatter the glass enclosures. They would also hunt and destroy any other animal housed with them.
With the remarkable vision and knockout punch, then why do mantis shrimp need all the color? The intricate and vivid colors and patterns on the body armor of mantis shrimp are used to communicate messages to other mantis shrimp. These messages are conveyed in patterns of ultraviolet and polarized light that is invisible to us but is vital for helping mantis shrimp to mate rather than smash each other to bits.
These signals may also have important applications in satellite sensing and cancer detection according to another study by University of Queensland scientists. Cancer cells reflect polarized light differently than healthy cells and scientists at Washington University in St. Louis are now attempting to develop a camera based off of mantis shrimp eyes to detect the cancerous cells with polarizing light sensors. This camera is also being used to screen baseball pitchers for damage to their ulnar collateral ligament (UCL) which leads to season-ending Tommy John surgery. These are just a few of the serious human health issues that the mighty biotechnology of the mantis shrimp is helping us solve.
The mantis shrimp’s evolutionary journey has also created incredible body armor with the ability to stand up as the shrimp throws punch after devastating punch. It accomplishes this through layers of polysaccharide chitin under the shell that are arranged in ways to absorb the shock of the shrimp’s punches. This armor is so impressive that it has even been studied by researchers to develop better, stronger body armor.
There are currently around 500 species of mantis shrimp around the world, and they are not closely related to anything else alive. Stomatopod crustaceans have been in the fossil record for about 400 million years and their super-specialized evolution has sent them on a drastically different path from other crustaceans during that time period. The mantis shrimp’s evolutionary journey has created incredible body armor, probably the best punch in the animal kingdom, and possibly the most specialized eyes in evolutionary history. All of these incredible traits make the mantis shrimp the super-powered terror of tropical sea floors, scoping out unsuspecting prey and smashing them to bits.
Sources:
https://theoatmeal.com/comics/mantis_shrimp
http://mentalfloss.com/article/86128/10-eye-popping-facts-about-mantis-shrimp
http://science.sciencemag.org/content/343/6169/411
https://www.uq.edu.au/news/article/2015/11/shrimp-vision-communication-and-cancer-detection
https://video.nationalgeographic.com/video/worlds-deadliest/00000144-0a29-d3cb-a96c-7b2d9d5c0000
