Leo E. Godin, age 11, of Albany, New York, for his question:
What are the habits of the crayfish?
An animal's life style is classed as natural history and natural history is just about the most fascinating study in this wondrous world. We share our planet with a multitude of different creatures and studying them is somewhat like getting to know the neighbors. What's more, when we understand even one humble little creature, we also learn his role in the complex balance of nature. We respect him and strive to protect his niche in the earth's ecology.
The crayfish prefers to list his habits as classified information. He lives a secret, solitary life and does his best to keep out of sight. Studying his life style calls for patient probing in the muddy bottoms of certain inland waters. He is an arthropod, a qualified member of the huge phylum of creatures who wear tough exoskeletons banded with joints of pliable material.
When fully grown, a six inch crayfish can be mistaken for the teenage offspring of a lobster. We need an item from natural history to tell the difference. The lobster is adapted to life in the salty seas. The crayfish belongs in fresh water. In North America, about 200 slightly different species live east of the Rockies and another five in the West. Several species live in muddy ponds and lazy creeks. Others prefer flowing streams; some live in wide rivers and a few in swift mountain streams. One species lives in marshy meadows, where he tunnels below the water and tops his burrow with a muddy chimney. The blind crayfish lives in the cool, calm waters of dark caves.
Their environments differ somewhat, but every crayfish has similar habits. As we know, he is a tasty morsel. This fact also is known to turtles and snakes, fishes and salamanders, otters and various water birds. The crayfish establishes habits to protect himself from a horde of hungry foes. His life centers on his solitary security tunnel, where he spends the dangerous daylight hours.
After dark, he ventures forth to forage for food. He pauses a cautious moment, facing his burrow and testing the neighborhood with his sensitive feelers. If things seem safe, he prowls around using his pincers to grab drifting eggs, larvae and small swimmers. The frisky hunter is an expert swimmer with eight skinny walking legs to scuttle forward, backward and sideways. But the cautious character strives to keep his tasty body in contact with sheltering mud and solid stones. And at all times he is ready to scoot into hiding.
In early spring, the solitary crayfish arranges for a brief honeymoon. Both parties return home and later the female lays 200 to 400 eggs. For several weeks, she carries them attached to her underside, like bunches of tiny berries. The youngsters molt many times as they grow. An adult crayfish molts perhaps once a year. While his new exoskeleton hardens, he takes extra precautions to stay out of sight, usually down in his muddy security tunnel.