system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What kind of information do dogs get from sniffing each other's butts? Why do they do it?
gpt
Dogs have sweet smelling anal sacs and the scent of which is unique to each individual dog.  It's a way dogs can get to know each other.  Dogs can also identify other dogs they've met by sniffing the feces or urine they've left behind and it's why most dogs seem to wipe their feet after peeing or pooping.  They sweat through their foots pads and it smears their own scent over the territory they've claimed.