Jackie Ranich, age 11, of Williamsport, Penn., for her question:
HOW DOES AN OCTOPUS BREATHE?
There are about 50 different kinds of octopuses living in various parts of the world. Most of them are about as big as a man's fist, although some grow to king size proportions. The largest in the world can measure 28 feet from the tip of one tentacle to the tip of another tentacle on the other side of his body.
Some people call the octopus devilfish. They probably do this because of the animal's most frightening appearance. The creature has a soft body and eight arms called tentacles. It also has large, shiny eyes and hard jaws that come to a point like a parrot's bill.
An octopus uses his arms to catch crabs, lobsters, muscles, clams and other shellfish. He then breaks them apart with his horny jaws.
Some octopuses inject a poison that paralyzes their prey. The creatures, however, very rarely attack people.
The octopus belongs to a group of shellfish called mollusks. He has no bones and no inside shell but a tough protective wrapper called a mantel covers his body and gives him shape. His tentacles are joined to the body and to one another by a web of tissue.
Rows of round muscles on the underside of each tentacle act much like suction cups. The cups fasten tightly to an object and continue to hold even if the tentacle is cut off. If a tentacle is lost, the octopus can grow a new one in its place.
The animal breathes by means of gills, somewhat as fish do. The gills are located near three hearts which pump blood throughout the octopus` body. He has two eyes and sees well. He has the most highly developed brain of all the invertebrates, which are animals without backbones. An octopus swims by drawing water into his body and then squeezing it out through a funnel shaped opening under the head which is called a siphon. The force of the expelled water makes the octopus move backward.
As a device often used to escape from sharks, men, whales and other enemies, the octopus can squirt a dark fluid from his siphon. The fluid makes a dark cloud in the water that gives the octopus a chance to escape.
Many octopuses can also change the color of their bodies to blend with their surroundings.
A female octopus can lay a cluster of as many as 180,000 eggs that are nearly transparent. The eggs become attached to rocks and then hatch in about two months. The female tends the eggs and does not eat during this two month period. As soon as the baby octopuses hatch, the mother takes off and the youngsters must begin to find their own food.