Communication in the animal kingdom is complex (and weird). When dogs smell each other’s butts, we can see a special form of chemical greeting.
A dog’s sense of smell is 10,000 to 100,000 times better than that of humans, and there are good reasons that dogs are interested in other canine butts. The anal sacs in a dog’s rear end contain glands that produce acidic chemical odors. From these chemicals dogs can learn about the other’s diet, gender, health, and emotional state. Dogs use a secondary olfactory system called Jacobsen’s Organ that specializes in chemical communications.