Dogs have a unique way of greeting each other, and it often involves sniffing each other’s rear ends. While this behavior is totally normal for dogs, it can be somewhat awkward when your dog decides to focus on sniffing your crotch. But why do they do this?

Dogs communicate with their sense of smell, which is far more advanced than humans. With 220 million scent receptors in their noses—about 50 times more than we have—dogs can detect odors that are undetectable to us. This keen sense of smell is how dogs explore their world and gather important information about their surroundings, including the people they meet.

So why the crotch? According to Jennifer Sperry, a veterinarian with Pets Plus Us Insurance, dogs are drawn to this area because it has a higher concentration of apocrine sweat glands, which produce a stronger, more distinctive scent compared to other parts of the body. These glands are also found in other areas like the armpits and chest, but the crotch is often more accessible and tends to have a stronger odor. For medium to large dogs, the height of the crotch also makes it easier to reach—something your guests might not find so comfortable.