while, and then swim down to the sea, 
or into a large lake if they are land¬ 
locked salmon. When the time comes 
to lay eggs, or spawn, they go back up 
the stream from which they came. 
Salmon do not live in this way because 
they think it the best way. They can¬ 
not think. Nature has made them in 
such a way that when they reach the 
right age, when their spawning time 
comes, some unknown call leads them, 
even from great distances, back to the 
place of their birth. Often they return 
even to the very branch of the stream 
in which they were born. And year after 
year each kind of salmon in each stream 
begins its run at exactly the same time. 
When the time for the run comes, the 
salmon begin to move in from many 
directions toward the mouth of the stream 
which was their first home. 
At first they go slowly. They swim 
about as if they were playing. Some 
19 
