Posted: 18/03/2013 at 09:42
The scent in these, er, materials does have a real value.
By sniffing the material, other canines can detect what the depositing animal ityself had been eating, and so know if there is food in the area.
The scent may be unattractive to us, but, presumably, the scent of a lady fox smells very attractive to male dogs, and conversely. They can't get enough of it.