Biology
Olfactory Imprinting and Natal Homing in Salmon
Quick fact
Salmon can distinguish their home stream from others based on a unique chemical 'bouquet' of dissolved minerals and organic compounds, and they learn this bouquet during a brief juvenile critical period.
Why this is interesting
A salmon that left its home stream as a fingerling can return years later to the exact same gravel bed, sometimes traveling thousands of miles. How does it find its way back with such precision?