Asked by: Luigi Sebastiano, by email
One theory is that it’s a hunting behaviour that evolved as a way to mask the dog’s own scent to make it easier to stalk prey.
It’s odd that a dog would choose the poo of another predator though. It may be that for most dogs, fox poo is the only really stinky poo they have access to. Cows and horses are kept away in their own fields and cats bury their poo neatly.