Alongside the Bloodhound and Basset Hound, the Beagle has one of the best developed senses of smell of any dog.In the 1950s, John Paul Scott and John Fuller began a 13-year study of canine behaviour. As part of this research, they tested the scenting abilities of various breeds by putting a mouse in a one-acre field and timing how long it took the dogs to find it. The Beagles found it in less than a minute, while Fox Terriers took 15 minutes and Scottish Terriers failed to find it at all. Beagles are better at ground-scenting (following a trail on the ground) than they are at air-scenting, and for this reason they have been excluded from most mountain rescue teams in favour of collies, which use sight in addition to air-scenting and are more biddable. The long ears and large lips of the Beagle probably assist in trapping the scents close to the nose. In the 1850s, Stonehenge recommended a cross between a Beagle and a Scottish Terrier as a retriever. He found the crossbreed to be a good worker, silent and obedient, but it had the drawback that it was small and could barely carry a hare.