The salmon is this determined navigator. Not only will it travel great distances to reach the place where it was born, but it swims against strong currents while doing so.
After salmon are spawned, or hatched from their eggs, in a stream, they swim out to the ocean, where within a year or two, they grow to lengths of four feet and weights of about 70 pounds. But when the egg laying season arrives, these same salmon return to their fresh-water streams and fight an upstream current all the way. They fight rapids and leap over waterfalls, some as high as 15 feet. During this journey, they do not even stop to eat.
When the salmon finds the exact stream in which it was born, found by its highly developed sense of smell, it lays its eggs in the bed of the stream. Some salmon die in those very streams, tired from the long and difficult journey, but others make the return trip to the oceans.