Why do dogs like to pee on fire hydrants?
Yes, it’s like a tree stump in a city. Dogs normally mark on trees, but cities have few of them so hydrants will do. They would pee on signposts but they are too narrow so they would miss. Hydrants are nice and fat, and just the right size. When they sniff hydrants they gather all kinds of information…. like Pippi the poodle was there that day and she’s in heat, or that Boris the wolfhound has a bladder infection or that Max the pit bull had fish for dinner. They sniff dried pee to gather data, the same way we surf the internet to learn about the world.