Salmon identify a specific spawning river using their keen olfactory sense.


"The salmon's extraordinary ability to locate the river where it was born is due to its highly developed olfactory sense, which enables it to distinguish between different rivers by scent." (Shuker 2001:76)

The Hidden Powers of Animals: Uncovering the Secrets of NatureJanuary 1, 1970
Dr. Karl P. N. Shuker