If the shrimp
we ate were anything like mantis shrimp, there would be a whole lot of nine-fingered fishers out there; pound for pound, there is no more dangerous predator in or out of the ocean. The diving community
has given them the apt nickname of "thumb splitters", and of the few people even aware of their existence, all most care to know is that these things can break your hand in a heartbeat. Biologists refer to them by the technical term stomatopods
, and aside from a few adventurous aquarists
, they are the only ones to appreciate the uniqueness and fascination of these crustaceans
They belong to the diverse class Malacostraca
, which encompasses shrimp
as well as crabs
); they belong to their own subclass Hoplocaridia
(“armed shrimp”) and order Stomatopoda
. They are further classified as either “spearers” or “smashers”, depending on the means by which they destroy their foes.
Mantis shrimp designated as spearers
wield sharp blades at the ends of their arms, which can neatly hole much larger fish
, or other soft-bodied animals. A dangerously barbed "finger" is folded up within a groove of this blade, able to snap out with the speed and force of a small-caliber bullet. Unfolding in eight milliseconds and travelling ten metres a second, it is among the fastest motions that any animal is capable of.
More aggressive still are the smashers
, with massive, calcified
elbow-clubs that they bring to bear against prey such as crabs
. They frequently obliterate crustaceans
much larger than themselves, reducing huge crabs
to delicious fragments. Clams
are picked up, leaned carefully against rocks, and broken open. This variety of mantis shrimp has a deserved reputation for being able to shatter aquarium
glass, although only the larger specimens have this level of strength.
Depending on their species, mantis shrimp grow from two to thirty centimetres in length. Their coloration ranges from drab gray or dun to a prismatic, riotous beauty. Although superficially resembling crayfish
in their body structure -- an elongated carapace
, eyes on stalks, and eight main legs followed by swimmerets
and a flexible lobsterlike tail or telson
-- their unique predatory arms make them immediately distinguishable.
One of the most fascinating aspects of stomatopod
anatomy is their highly developed vision system, far surpassing that of humans
and almost all other forms of life. Each crazily spinning, stalked compound eye
has three separate regions: upper and lower hemispheres that serve mainly to pick out forms, separated by a color-sensing midband. As a consequence, each eye can see an object from three different perspectives, and has depth perception
vision on its own. (We need both eyes
for depth perception
and mere binocular
The middle band of the mantis shrimp's eye
is equipped with ten different varieties of visual pigment
, as opposed to our eye's
three (red, green and blue). Eight of the mantis shrimp's pigments
are dedicated to color vision alone; their visible spectrum, encompassing eight primary colors
, is the key to a visual world unimaginable to humans
. They can identify roughly ten thousand distinct colors, compared to the human maximum of one thousand. The additional pigments are dedicated to viewing the polarization
and distribution of light, qualities human eyes
can only faintly perceive, but which are essential in the low-contrast
is likewise highly developed; researchers have shown it to be roughly equal to that of that notorious unbackboned intellectual
, the octopus
. Mantis shrimp can be trained to differentiate exceedingly similar colors and geometric shapes, and solve simple puzzles such as unwrapping a rubber band from a food item.
Mantis shrimp are the only invertebrates
which can be consistently shown to discriminate between individual members of their species; this is probably a result of fierce competition for a limited amount of suitable living spaces
, leading them to view competitors as unique individuals, and treat them intelligently. Certain species are even monogamous.
have a fairly wide distribution throughout the shallow and warm waters of the world, found ten to twenty metres down in areas as diverse as Indonesia
, and the Isle of Wight
. Some species burrow exclusively, tunneling through sand and mud, whereas others prefer pre-formed caverns in coral reefs
and rocks. They spend the majority of time tucked neatly inside their lairs, waiting for unsuspecting creatures to come close; extremely wary of their relatively undefended backsides, they seek shelter whenever possible. Some species are known to block their lair entrances with rubble at night.
Like all crustaceans
, they are egg-layers; the female can store fertilized
eggs for three months or more after copulation. Eggs are exuded in a globby
mass that she carries around with her until they hatch; typically the larvae
leave immediately, although in a few species, they stay with their mother for a week or ten days before seeking their fortune, progressing through several larval and juvenile growth stages. Larvae are ferocious and cannibalistic
, which explains the limited success of rearing them in home aquaria
. Even in their earliest growth stages, their fearsome forelimbs are present, and frequently used to dismember other larvae
The average lifespan of a captive mantis shrimp is three to four years, and researchers estimate that they may live much longer in their natural habitat, with certain species able to exceed twenty years.
The fascination of these creatures makes their relative obscurity all the stranger. They could teach us a thing or two; not just about eating clams
and being pretty, but about percieving wonderful psychedelic
landscapes, and kicking lots and lots of ass. And in the end, isn’t that what it’s all about?