Loren Rucker, age 7, of Douglass, Kan., for his question:
What are lampreys?
Every animal has a few bad habits. Bears can be mean and cats can scratch. Bears also are charming clowns, and Miss Puss is an expert mouser. Almost every animal has more good points than bad points. But not the lampreys. No one has a kind word to say about them.
These snaky fellows live in creeks and ponds, lakes, and rivers and some of them live in the sea. But wherever they live, the lampreys are unpopular. Fishermen hate them. Game wardens and experts who work to conserve and protect the creatures of the wild hate them. Scientists search for chemicals to destroy them. The governments of the United States and Canada are united in a war against them.
The small lampreys of the creeks and ponds are about eight inches long. The largest lampreys of the sea are two or three feet long. They have no real bones and no real teeth. They have no scratchy prickles and no deadly stings. You may wonder what these smallish animals do to make everyone detest them. Lampreys are unpopular because they are parasites. This means that they live and feed upon living animals. The lampreys are uninvited guests who suck the blood and body juices of live host animals.
You might mistake a lamprey for a slippery eel. His shiny skin is muddy brown or mottled with dirty gray. Though he lives in the water he is not a true fish. He has no scales and no bones, and his simple backbone is made of gristle. Most of his small head is occupied by a round, saucer shaped mouth.
The mouth of the lamprey is built for sucking the blood of his victims. Its sides are lined with toothy bumps, and in the center there is a round rough tongue. His victims are trout and other fish that fisherman like to catch in the streams and rivers. He also attacks food fish and many other fishes of the sea.
When he finds a victim, the lamprey fixes himself on its side or back with his sucking mouth. He uses his tongue to rasp a hole through the fish's scaly skin and sucks out the blood. The living victim soon becomes weak and often dies.
Some years ago lampreys invaded the Great Lakes. There they attacked and destroyed countless thousands of useful fishes. Something had to be done to protect the last of the food fishes in the lakes. The U.S. and Canadian governments are working together to trap and poison the lampreys. In some places they have set up electric fences to destroy the greedy little parasites.
In spring when the time comes to spawn, the parent lampreys leave the seas and lakes, creeks and ponds. They travel to clear inland streams and lay their eggs in the gravel under the shallow water. The wormy youngsters drift to deeper streams and bury themselves in the mud. Only their round mouths poke above the mud, always open to catch drifting scraps of food. After three or four years they are grown and ready to invade the waterways