Using their swiveling ears like radar dishes, experiments have shown that dogs can locate the source of a sound in 6/100ths of a second. Though human noses have an impressive 5 million olfactory cells with which to smell, sheepdogs have 220 million, enabling them to smell 44 times better than man.

Sense of smell is general knowledge for dogs but very nice point about dogs hearing ability. I wonder if they use this for general purposes.