(Phys.org) —Researchers with the University of Queensland, Brisbane along with an associate from National Cheng Kung University, in China have found what they believe to be a reasonable explanation for mantis shrimp having 12 photoreceptors in their eyes.
In their paper published in the journal Science, the team describes a study they conducted where shrimp were trained to respond to different colors, which led to the discovery that despite more receptors than most other organisms, they are less able to discriminate between different colors—a finding that indicates they process colors in a different way. Michael Land and Daniel Osorio offer a Perspective piece on the researchers efforts in the same journal issue.
Scientists have known for many years that mantis shrimp have more photoreceptors than most other organisms, but have not, until now, been able to come up with a reason why. The assumption had been that the creatures had some special vision abilities that allowed them to see things that others could not. In this new effort, it appears that the large numbers of receptors adds a speed advantage rather than visual enhancement…
Ferocious, Fearless Mantis Shrimp Is the Honey Badger of the Sea
by Matt Simon
These are the stomatopods, some 550 known species of mantis shrimp that range from less than an inch long to well over a foot. They’re feisty, beautifully complex creatures that strike so quickly that they momentarily superheat the water around their spring-loaded clubs to a temperature nearly as hot as the surface of the sun.
They may not be particularly big, but they will fight just about anything that so much as looks at them funny. Octopuses, humans, each other — you name it. You see, the mantis shrimp doesn’t grab ass. It kicks it.
Mantis shrimp are split into two groups. Smashers methodically dismember and knock their prey unconscious. Spearers impale fish with spikey appendages, much like their insect namesake. The speed and power with which these creatures strike simply defies logic. While the spearers can lash at their prey in a mere 20 to 30 milliseconds, the smashers can be 10 times as quick. This is the fastest predatory strike on the planet…
Tiny, deadly and gorgeous. That’s the peacock mantis shrimp, and we just placed one on exhibit in our Splash Zone galleries.
You’ll have to work a bit to see it. It’s housed — alone — in a small aquarium inside the Coral Crawl tunnel in Splash Zone. But it’s well worth the effort!
This is the first time we’ve hosted a mantis shrimp since 2001 when one of them stowed away inside some coral rock and earned us international headlines and live CNN coverage. (There’s something compelling about a “killer shrimp” terrorizing other animals in the children’s area of an internationally known aquarium.)
They pack quite a punch
Since then, we’ve been wary of deliberately introducing a mantis shrimp — and for good reason. Aquarists and scuba divers refer to them as “thumb-splitters” because their claws pack a punch as powerful as a .22-caliber bullet.
He starts by examining the eyes that make them unbelievably effective hunters. Their vision is so sensitive that a mantis shrimp can see in both infrared and ultraviolet spectra, and uses 16 color receptor cones (compared to just three for humans).
How ‘Smashing’ & ‘Spearing’ Shrimp Speedily Attack Prey
by Douglas Main
Spearing mantis shrimp hide in their burrows and wait for an unsuspecting creature to come along. Then, in the blink of an eye, they spear it with their long claws, like an underwater archer. How do they spear their prey so quickly?
Maya deVries, a researcher at the University of California, Berkeley, compared the attack of the spearing shrimp with its relative, the “smasher” shrimp. Both animals are able to unleash quick attacks with a strange spring and latch system that stores up energy in their muscles and releases it in an instant. It’s like a bow and arrow, she said.
Unexpectedly, she found that smasher mantis shrimp can move much more quickly than the spearing variety, which is the opposite of what was expected. The smashers, she found, need quick speeds to produce enough force to crack the shells of their prey, such as crabs and other shellfish. The spearing shrimp, on the other hand, only needs to move slightly faster than their prey, she said…
(read more: LiveScience) (photo: Roy Caldwell/UC Berkeley)
The Peacock mantis shrimp (Odontodactylus scyllarus) is capable of firing its clubbed claws at over 80 km/h (50 mph), with an acceleration similar to a .22 caliber bullet. The shrimp uses its club both for defense and offense, and can generate 90 kg (200 pounds) of force. The strike is so fast, it boils surrounding water, creating cavitation bubbles that immediately collapse under water pressure, striking the prey a second time. The collapsing bubble also creates a short lived flash of light and temperatures of several thousand kelvin.
If sea creatures were Marvel comic book characters, the peacock mantis shrimp would be Thor. These colorful crustaceans have a hammerlike claw that can smash prey with the acceleration of a 0.22-caliber bullet — not unlike the superhero’s mythological weapon.
Now, a new study reveals the secrets behind the strength of the mantis shrimp's claw at the molecular level. It turns out this appendage is ideally adapted to deliver punishing blow after punishing blow without breaking. These adaptations are already inspiring researchers to engineer biology-mimicking materials that could inspire everything from better boat propellers to safer body armor.
"What makes [mantis shrimp claws] so incredible is that they’re stiff and they’re also tough, which is really kind of an inverse relationship in materials science," said study researcher David Kisailus, a materials scientist at the University of California, Riverside…
Mantis shrimp or stomatopods are marine crustaceans, the members of the order Stomatopoda. They are neither shrimp nor mantids, but receive their name purely from the physical resemblance to both the terrestrial praying mantis and the shrimp. They may reach 30 centimetres (12 in) in length, although exceptional cases of up to 38 cm (15 in) have been recorded.
Mantis shrimp appear in a variety of colours, from shades of browns to bright neon colours. Although they are common animals and among the most important predators in many shallow, tropical and sub-tropical marine habitats, they are poorly understood as many species spend most of their life tucked away in burrows and holes.
These aggressive and typically solitary sea creatures spend most of their time hiding in rock formations or burrowing intricate passageways in the sea bed. They either wait for prey to chance upon them or, unlike most crustaceans, actually hunt, chase and kill prey. They rarely exit their homes except to feed and relocate, and can be diurnal, nocturnal or crepuscular, depending on the species. Most species live in tropical and subtropical seas (Indian and Pacific Oceans between eastern Africa and Hawaii), although some live in temperate seas.