This is why dogs pee on car tires.
It leaves an invisible dotted line they can follow if they
get lost.
My old hound "Trooper" got lost once, he was gone for two weeks, finally my ex who was a pet sitter was making a call
on the other side of Atlanta and there he was sitting on
the porch waiting for her, like "Where you been?".
The only alternative was space alien abduction, which
would have been a first for a dog, at least as far as we know.
Maybe he was one of the 4400? I think that's how we GOT our dog. One day he just appeared. Don't recall a flash of light, but I might have been asleep.
;)
I've actually read Elizabeth Marshall Thomas' book. She was your classic Cambridge eccentric. She kept a house full of work dogs, mostly sled dogs, and would take them for walks around the city. That was during the day.
She discovered that the alpha male would get loose at night, and she wondered where he went. So she started following him in his travels in the wee hours (that's the chapter Dave Barry summarizes:) This dog could cross busy highways without getting hurt, once even got as far as Concord, quite a trek from Cambridge (10 mi+).
What was really unusual is that she didn't train her dogs, just allowed them to live according to their own instinctive wolfpack rules, and recorded their behavior.
A fascinating read.