Once a dog reaches about 50 pounds and has a 'traditional pointed snout' which is to say not brachycephalic( push faced, like a pug..) They seem to top out at about 220 million Olfactory Sensory Neurons. Much to the dismay of bloodhound fans, a great deal of what you hear about them is myth.
That said however bloodhounds can sometimes do what seems like the remarkable. They are hard wired to track, and nothing else. With what we shall call an uncluttered mind,they are not as prone to distraction as some others. A GSD on a track for instance is thinking a mile a minute. Will he find the bad guy, will he get a bite , will there be a fight? The bloodhound simply wants to know where the track ends....
I have heard bloodhounds, and beagles for that matter have about 300 million OSNs but have never seen a citation or research to back it up.
