Marineland of the pacific - A Fascination for Fish: Adventures of an Underwater Pioneer - page 24

Walter, who thoroughly enjoyed designing and making gadgets, next
built the Big Bertha of all slurpers. Six feet long and six inches in di-
ameter, the acrylic plastic device was powered by four speargun rub-
bers. It was cumbersome underwater, but I was able to collect the ten-
inch-long mantis shrimp ( Hemisquilla ensigera ) by literally sucking them
out of their sandy seafloor burrows. When I spotted a shrimp's stalked
eyes peeking out of a hole, I placed the clear end of the gun barrel over
its burrow. I waited until the shrimp came up for another look, then
quickly pulled the trigger. The powerful gun sucked a crater in the bot-
tom and instantly filled with sand, shells, and a very irate mantis shrimp
frantically dashing and whacking about inside the slurp gun.
Despite their common name, these strange creatures are not true
shrimp. The mantis part of their name comes from their praying
mantis-like front appendages. These are tools well adapted for seizing
and dismantling prey, and they a¤ord good protection from predators.
The most remarkable feature of these appendages is their lightning
speed: they shoot out faster than the human eye can follow. The lower
part of their hinged claw is blunt and is used like a hammer for crack-
ing hard-shelled clams. The extensible tip is like a needle and can pierce
their prey, while the razor-sharp inner edge of the hinged arm can slice
their prey in half. It's the animal equivalent of a Swiss army knife! Com-
mercial fishermen know the mantis shrimp by the very apt name of
“thumb splitter.”
The e¤ectiveness of mantis shrimp tools became vividly clear to me
when, back on the boat, I scooped one up in my dive mask to trans-
fer it to another container. It shot out its weapon and pierced clear
through the tough rubber of the mask; unable to pull out, it just help-
lessly hung there. Another time, I was temporarily moving a mantis
shrimp out of my home aquarium to clean the tank. Knowing some-
thing of their capacity to shred nets and fingers, I carefully scooped it
into a large glass tumbler. Suddenly there was a loud crack and the glass
shattered.
This species of mantis shrimp has two brilliant red, blue, and yellow
false eyespots on its tail. Many widely di¤ering animals, from insects to
fishes, use false eyespots to confuse or startle potential predators.