10 Eye-Popping Facts About Mantis Shrimp

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iStock

"Beautiful" and "deadly" are two descriptors you don’t typically see attached to shrimp. But the mantis shrimp is in a class of its own. This colorful specimen has earned a reputation for being one of the most fearsome creatures of the deep. Here are 10 facts worth knowing about the pint-sized bruisers.

1. THEY’RE NOT SHRIMP.

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Despite their namesake and relatively puny stature, mantis shrimp aren’t shrimp at all. (Neither, of course, are they mantises.) They're stomatopods, distant relatives to crabs, shrimp, and lobsters.

2. THEY PACK A POWERFUL PUNCH.

The peacock mantis shrimp (Odontodactylus scyllarus) uses two appendages called dactyl clubs to pummel its prey like aquatic Rock 'Em Sock 'Em Robots—that is, if kids’ toys could punch fast enough to boil water and split fingers to the bone. These wrecking ball "fists" spring forth from their bodies at 50 mph, accelerating quicker than a .22-caliber bullet. At those speeds, the water surrounding them briefly reaches the temperature of the Sun’s surface. When the dactyl clubs hit their target, they deliver 160 pounds of force, smashing through shells like a lightning-fast crab mallet.

3. THERE ARE HUNDREDS OF SPECIES.

Mantis shrimp come in a variety of species, and we’re aware of about 550 of them. Stomatopods from different species range in size from smaller than an inch to longer than a foot. They’re usually classified by murder method—either smashing, as detailed above, or spearing. In place of dactyl clubs, spearers have two sharp appendages on the front of their bodies built for harpooning prey. Spear-wielding mantis shrimp don’t move as fast as their club-fisted counterparts (their strikes are about 10 times slower), but the threat of death by impalement is intimidating on its own.

4. THEIR VISION IS UNPARALLELED.

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Peacock mantis shrimp have the most complex set of peepers in the animal kingdom. Each eye contains 12 photoreceptors that allow them to sense different types of color. For comparison, human eyes typically contain three types of light-sensitive cells for seeing red, blue, and green. This has led some to conclude that mantis shrimp perceive the world in a psychedelic rainbow of vibrant color we can’t begin to comprehend. But in reality, the crustaceans are actually worse at differentiating between subtle variations in hue than we are.

A study from the University of Queensland found that when mantis shrimp were shown colors with a difference in wavelength less than 25 nanometers, they had trouble telling them apart. But just because mantis shrimp may not see the variations between powder blue and periwinkle doesn’t mean their vision isn’t extraordinary. On the contrary, their optic abilities are on a completely separate level from ours, functioning more like a satellite than anything found in nature. Scientists believe that mantis shrimp take all the visual information they see into their brains at once without processing it, allowing them to react to their surroundings as quickly as possible. Their independently roaming eyes and trinocular vision also make them excellent hunters.

5. THEY SHARE A SECRET LANGUAGE.

Roy Caldwell, University Of California, Berkeley

 
In addition to the all epic abilities listed above, mantis shrimp are one of the only creatures capable of seeing polarized light. This has allowed them to develop a secret code that’s undetectable to other species. The Haptosquilla trispinosa species of mantis shrimp wields feathery feeding appendages called maxillipeds that are marked with iridescent, blue spots. The cells of these features reflect light in a unique way. Instead of bouncing light into a reflective structure like the polarizing cells developed by humans, the cells distribute light across the spot’s surface. The brilliant light is plainly visible to other mantis shrimp, allowing them to signal members of their species while staying hidden from predators.

6. YOU WON’T FIND THEM IN MOST AQUARIUMS.

Prilfish via Flickr // CC BY 2.0

You’d think a mantis shrimp’s technicolor exterior would make it a staple at most aquariums, but this creature is rarely kept in captivity. The same dactyl clubs that allow them to shatter shellfish are also capable of cracking a glass tank. When aquariums do accept a ruthless specimen into their collection, it must kept behind shatterproof acrylic glass. On top of that, a captive mantis shrimp needs to be the sole occupant of its specially constructed home, lest it decides to treat its tank-mates as punching bags.

7. THEY MAKE MENACING SOUNDS.

Elias Levy via Flickr // CC BY 2.0

It’s only natural that a creature as ferocious as the stomatopod would have a threatening call to match. California mantis shrimp have been known to make low, rumbling growling sounds both in the wild and the lab. Male mantis shrimp often emit grunts at dawn and dusk, the periods of the day when they’re most likely to be hunting for food or guarding their homes. Scientists theorize that the growls are meant to attract mates and ward off competitors.

8. THEY’RE HELPING SCIENTISTS BUILD BETTER BODY ARMOR.

Jens Petersen via Wikimedia Commons // CC-BY-SA-3.0

 
The mantis shrimp’s super-powered punching abilities raise a puzzling question: How can the animal deliver such a deadly blow without injuring itself? To get to the bottom of the mystery, researchers looked at the composition of the peacock mantis shrimp’s built-in weaponry. They found that the creature’s dactyl clubs consisted of an outer coating of hydroxyapatite, a hard crystalline calcium-phosphate ceramic material. Beneath the surface lies the key to the animal’s anti-fracturing qualities. Layers of elastic polysaccharide chitin underlying the shell are positioned in a way to act as shock absorbers, reducing the possibility of cracks. The design is so effective that researchers modeled a new type of carbon fiber material after it with potential applications in aircraft panels and military body armor.

9. THEY PRACTICE SOCIAL MONOGAMY.

Barry Peters via Wikimedia Commons // CC BY 2.0

The life of a mantis shrimp isn’t all cold-blooded killing. Some species of stomatopods are known to engage in the rare practice of social monogamy, a behavior that’s especially remarkable among crustaceans. This means mantis shrimp will choose one partner to share food, shelter, and raise offspring with over the course of a lifetime. What may sound romantic to humans serves a practical purpose for mantis shrimp. Research has shown that certain mantis shrimp tend to cluster outside reefs instead of living in the heart of the action. Without the need to go looking for someone new to mate with on a regular basis, mantis shrimp couples are able to enjoy a relatively safe, sedentary lifestyle secluded from predators.

10. THEY’RE OLDER THAN DINOSAURS.

Derek Keats via Flickr // CC BY 2.0

Stomatopods began evolving independently from other crustaceans nearly 400 million years ago, about 170 million years before the first dinosaurs appeared on the scene. Since then they’ve followed an isolated, evolutionary lineage that’s resulted in some of their more unique characteristics. Their biology is so bizarre that scientists have assigned them the nickname "shrimp from Mars."

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The Hidden Meanings Behind 11 Common Tombstone Symbols

Tombstone symbols can sometimes be hard to interpret.
Tombstone symbols can sometimes be hard to interpret.
Photo by Brett Sayles from Pexels

Walk through any cemetery in the world and you’ll find a solemn landscape that honors loved ones that have passed on. Accompanying the inscriptions of names, dates, and family crests are some common symbols that crop up repeatedly on tombstones. If you’ve ever wondered what they could mean, take a look at some of the explanations behind the graveyard graphics.

1. Eye

The eyes have it.Valerie Everett, Flickr // CC BY-SA 2.0

If you feel someone may be looking at you in the cemetery, you might be near a tombstone engraved with an eye. Often surrounded in a burst of sunlight or a triangle, an eye typically represents the all-seeing eye of God and could denote that the decedent was a Freemason.

2. Clasped Hands

Hands on a tombstone can mean several things.Christina Ramey, Flickr // CC BY-SA 2.0

Seeing two hands clasped together can illustrate shaking hands or holding hands, depending on the position of the thumbs. A handshake can mean a greeting to eternal life. If clasped hands have different cuffs, it could indicate a bond between the deceased and a spouse or relative. If one hand is higher than the other, it could also mean that a person is being welcomed by a loved one or a higher power. The hand engraving grew into wide use during the Victorian era.

3. Dove

Doves appear in a variety of poses on tombstones.Tim Green, Flickr // CC BY 2.0

A dove usually symbolizes peace and the Holy Spirit, but its specific meaning depends on how the bird is posed. If it’s flying upward, the soul is ascending to heaven. If it’s flying down, it represents the Holy Spirit arriving at the baptism of Jesus Christ. If it’s holding an olive branch in its mouth, it refers to an ancient Greek belief that olive branches could ward off evil spirits.

4. Broken Chain

Chains on tombstones can be linked or broken.Carl Wycoff, Flickr // CC BY 2.0

Medieval wisdom once held that a golden chain kept the soul in the body. In death, the chain is broken and the soul is freed. If the chain is unbroken and if it features the letters FLT (for Friendship, Love, and Truth), it probably means the deceased belonged to the Independent Order of Odd Fellows, a fraternal organization that seeks to promote charitable causes and offer aid.

5. Book

The meaning of a book on a tombstone isn't always easy to read.Carl Wycoff, Flickr // CC BY 2.0

Was the deceased an avid reader? Maybe, but not necessarily. An open book on a tombstone might refer to a sacred text like the Bible, the “book of life,” or the person’s willingness to learn. If you see a dog-earned corner on the right side, it could indicate the person’s life ended prematurely and before their “book” was finished.

6. Finger Pointing Up

An index finger pointing up can direct visitors to look up.Christina Ramey, Flickr // CC BY-SA 2.0

A hand with the index finger raised skyward is one of the more ambiguous symbols found in graveyards. It might be pointing to heaven, or indicate the fact that the decedent has risen from the land of the living.

7. Corn

Ears of corn could mean the deceased was a farmer.mike krzeszak, Flickr // CC BY 2.0

A corn stalk on a tombstone means the deceased could have been a farmer; it used to be a custom to send corn instead of floral arrangements to a farmer’s family. It might represent other kinds of grain. Alternately, corn seeds can symbolize rebirth.

8. Scroll

Scrolls on a tombstone can refer to an unknown future.Kelly Teague, Flickr // CC BY-SA 2.0

A scroll engraved on a tombstone with both ends rolled up can indicate that part of life has already unfolded while the future is hidden.

9. Lamp

Lamps can mean a love of knowledge.Sean, Flickr // CC BY-ND 2.0

A lamp on a tombstone could speak to a love of learning or knowledge, or it might refer to how the spirit is immortal.

10. Camel

Camels aren't something you'd expect to see on a tombstone.Glen, Flickr // CC BY 2.0

While this particular camel signifies the Imperial Camel Corps that occupied desert regions during World War I, a camel can also represent a long journey or a skilled guide—in this case, for the afterlife.

11. Hourglass

An hourglass can be a message to the living.justiny8s, Flickr // CC BY 2.0

As you may have guessed, the hourglass symbolizes the march of time. An hourglass on its end may mean the deceased died suddenly, while a winged hourglass communicates how quickly time flies. It may also be construed as a message to the living—time is short, so don’t waste it.