Did you know...the old adage that a dog's mouth is cleaner than a humans is false? Researchers at Stanford University found that on average, a human mouth contains 37 types of bacteria. At the University of California, reserchers found that on average, a dog's mouth contains 53 types of bacteria. Also, contrary to popular tales, a 1988 study published in the Annals of Emergency Medicine found that humman bites do not have a higher rish of infection than animal bites--both are around 10%. The danger rate only goes up if untreated.