An animal made of water
A strange shape moved slowly through the dark-blue water of a tropical
sea. It looked like a see-through umbrella. But instead of a handle, it
had ragged, lacy strips and strings hanging down from it. It moved
steadily forward through the water, rising and falling as it went. All
the time, the umbrella shape was opening and closing, opening and
closing.
A small, bright-colored fish appeared, swimming slowly with little
flicks of its tail. As if curious, it swam toward the dangling strings
that hung from the umbrella shape. It brushed against them.
Suddenly the fish found itself stuck! It tried to struggle, but a
strange numbness was spreading through its body. In a short time, it was
unable to move. Slowly, the stringlike tentacles that held it began to
lift it up toward the umbrella shape—where a hungry mouth was waiting!
This strange, umbrella-shaped creature with the thin, hanging tentacles,
is called a jellyfish. It is an animal whose body is made almost
entirely of water. When, as often happens, a jellyfish is left stranded
on a beach by the tide, it looks like a lump of clear jelly. But when it
dries up in the sun, only a wet, sticky spot is left.
This watery creature gets along very well in its watery world. Upon its
umbrella-shaped body are little \”pits” with which it smells. And there
are little eye-spots with which it can make out light. It swims by
opening and closing its body, much the way an umbrella opens and closes.
Each time it closes its body, water is squeezed out from beneath it and
the jellyfish is pushed upward.
The tentacles and body of most kinds of jellyfish contain many tiny
\”bubbles” in which there is a coiled-up, threadlike tube. These tubes
are filled with a poison. When something touches a tentacle, the little
bubbles explode and shoot out the poisonous threads. The poison
paralyzes the victim.
There are many different kinds of jellyfish. Some are no bigger than a
pinhead. Others are giants, with bodies eight feet (2.4 meters) wide and
tentacles two hundred feet (60 m) long. There are jellyfish with bodies
like umbrellas, like bowls, like bells, like mushrooms, and like broad,
flat dishes. They are all transparent, but they often glow with
color—pink, blue, green, or purple.
Some kinds of jellyfish are a number of creatures joined together. One
such jellyfish is called the Portuguese man-of-war. And it does look a
little like an old sailing ship, or man-of-war, drifting on the water.
One of the many parts that make up this jellyfish is a sort of bag
filled with gas. This bag floats on the surface of the water. It looks
like a beautiful, pale-blue balloon with a pink ruffle along the top.
Hanging from the bag are a number of tubelike mouths and stringlike
tentacles. Each mouth and each tentacle is actually a separate animal!
The tentacles of some jellyfish can give people painful stings. And the
sting of one kind of jellyfish, called a sea wasp, has even killed
people!
