system
Given the following post, respond as if you're commenting on Reddit:
human
Why do dogs prefer to pee on vertical objects?
gpt
Animals navigate in much the same way that we do and use significant landmarks as waypoints and aids; like like boulders and tall trees. And in a modern context, lampposts and fire hydrants. 

Urination is used as a navigational aid, a literal breadcrumb trail when exploring new places, as well as for marking out territory or signalling presence, or just urinating. 

If you watch a dog on familiar territory after a heavy snowfall, their reaction can range from excitement to anger. Even though they know the territory well, all of the landmarks are "gone" as well as the scents, which results in a lot of confusion.