It's common knowledge: Bloodhounds find their quarry. But until recently, the scientific literature has been nearly silent on it. Physiologist Lisa Harvey, of Valley Victor Community College in Victorville, Calif., who is married to a police officer, decided to test the bloodhound's renowned sense of smell when some of the police officers, who use these animals to track criminals, could not get the courts to accept evidence found by the dogs.
She and her students tested eight bloodhounds, both novices and experienced trackers, which work in California law enforcement.1 They tested dogs on trails walked by volunteers in various places, including city streets, parks, and a college campus. In one case, more than 1,000 people crossed the trails before the dogs were tested. Harvey collected scent samples from the trail-layers and, at least 48 hours after the trails were walked, let the dogs pick up the scent. In most cases, ...
