Places you will read about: Africa: one of the seven continents. Nile River: a large river in Africa. Things you will read about: barracuda:a dangerous ocean fish, plover: a small bird.
As humans, we learn early in life that keeping clean helps keep us healthy. We learn to bathe and brush our teeth . We wash our hands often. Sometimes it seems that animals, as well as humans, understand that being clean is important. Often one sees an animal, such as a cat, cleaning itself with its tongue. But did you know that animals sometimes clean each other and help each other, much as humans clean and help each other?
"Yes," you may say. "A mother cat cleans her kittens."
But you may be surprised to know that there are also animals who do not belong to the same animal families who clean and help each other in this way. Far away in Africa, the fierce and dangerous crocodile suns itself on the bank of the Nile River. Crocodiles eat many birds and fish that they capture and swallow whole. Crocodiles are also known as fierce man eaters, causing distress to any native who comes upon a crocodile by accident. The sight of this animal is enough to terrify a native, and natives kill crocodiles whenever they can.
The African native greatly fears the crocodile, and thus it would seem that little birds and animals would feel the same way. How, then, do we explain the behavior of the "crocodile bird," or plover, who lives along the mud flats of the Nile River? The plover acts, in some ways, as the crocodile's helpful partner. It might be expected that the crocodile would terrify the bird, and yet the crocodile does not.
Small living things attach themselves to the crocodile. the crocodile can't shake off insects, or pick them from its body. But its partner, the plover, likes to eat them. The plover flies down, lands on the crocodile, and feeds. The bird does not show signs of distress. The crocodile lies still and accepts help with great patience. The crocodile even opens its mouth for the bird. Thus, the plover finds the living things that attach themselves to the crocodile's tongue and gums. The bird flies into the crocodile's mouth to remove harmful bits of animal life. The plover has no fear that the huge mouth will close upon it. If that happened, the bird would be held captive and eaten. The plover satisfies its own hunger while helping the crocodile keep its body free of harmful animal life.
In the sea world, as well as on land, there are other unusual partners who cooperate in a cleaning service. Deep in tropical seas are fish as fierce and dangerous in their territory as the crocodile is in its area. Fish such as sharks and barracudas use their sharp teeth to attack smaller fish before eating them. Yet there are over forty kinds of little "cleaner fish" that are in no fear of these terrors of the sea.
The "cleaner fish" are all brightly colored and easy to spot in the clear seas where they live. They usually stay in rocky areas, almost as if these were their shops for the business of cleaning, Many larger fish swim long distances to. visit the "cleaner fish," and the larger fish wait their turns, much as you would wait in line at a busy store. Each large fish is cleaned in its turn. When the cleaned fish swims away, another fish takes its place. Sometimes the waiting fish show patience, but at other times they are so eager to be next that fights may start.
When the "cleaner fish" is ready to work, it may do a swimming dance around the "customer fish. " The customer rests quietly in the water so that it can be worked on. If the customer is very large, several cleaners may share the job. Just as with a crocodile, tiny pieces of animal life attach themselves to the bodies of the fish. The little "cleaner fish" nibbles away at the scales of the larger fish, eating bits of dirt and attached living things. These become food for the "cleaner fish," as insects do for the plover. If the customer fish has been hurt, the "cleaner fish" eats away the dead flesh, thus cleaning the wound.
Often the customer fish moves its body so the "cleaner fish" can get into some of the areas that are difficult to reach. Sharks have been known to open their mouths and let the "cleaner fish" work all the way down their throats and then swim out again. As with the plover, the "cleaner fish" has no fear that it will become a captive in the larger animal's mouth. Any other fish would be harmed or eaten. But the "cleaner fish" will be safe. It might seem that sharks and other fierce fish would terrify the cleaners. But they do not. All through the world there are creatures who help each other. Many living things that serve other living things get something in return. The cleaners are an interesting example of such a group.
As humans, we can understand the need to be clean. And we can appreciate the need of two living beings to cooperate for the advantage of each other.
1. African natives ___________________
2. The plover _____________
3. The plover _____________
4."Cleaner fish" _____________
5."Cleaner fish" _____________
6. The large ocean fish _____________
7. The shark does not eat the "cleaner fish" because _____________
8. The plover and the "cleaner fish" _____________
9. Another name for this story could be _____________
10. The main idea of this story is _____________