How is it that a k9 can sniff out a persons scent and find somebody? I think its amazing? Also was wondering?

Question

how does the dog know the person is a danger or is missing? And how many miles away can they smell up to?

Answer 1

A dogs nose is like a thousand times more sensitive than a humans nose. Where you or I will smell the cake, the dog smells each ingredient in the cake. Since a human is always shedding skin cells, the dog will pick up on what we drop, that's what bloodhounds sniff when they are searching.