First listen and then answer the question: What caused the fire?
At last, firemen have put out a big forest fire in California.
Since then, they have been trying to find out how the fire began.
Forest fires are often caused by broken glass or by cigarette ends which people carelessly throw away.
Yesterday, the firemen examined the ground carefully but were not able to find any broken glass.
They were also quite sure that a cigarette end did not start the fire.
This morning, however, a fireman accidentally discovered the cause.
He noticed the remains of a snake which was wound round the electric wires of a 16,000-volt power line.
In this way, he was able to solve the mystery.
The explanation was simple but very unusual.
A bird had snatched up the snake from the ground and then dropped it onto the wires.
The snake then wound itself round the wires.
When it did so, it sent sparks down to the ground, and these immediately started a fire.