Wolves frequently use surprising things such as plastic or glass bottles, metal or plastic cans, rubber or leather boots, bones, antlers etc. They carry them, gnaw them, play with them, demonstrate them to another wolf etc. In my research practice on wolves I registered such a wolf behavior for many times, and gradually I started realizing, why wolves deal with the mentioned seemingly strange things. I might be not entirely right in the ideas, but anyway would like to share them as well as the photos taken.
These strange things are used by all three categories of wolves: adults, subadults and pups. Adult wolves apply them, perhaps, to dominate somehow over other individuals with more or less the same hierarchy status, for instance, between subordinated individuals within a pack. It means, if one wolf has such a thing, but another wolf does not have it, so, that one with the thing is more important. Adult territorial wolves apply such things for marking the home range by putting them on a visible point along a plausible route of other wolves and by urinating on them. For wolves it seems to be the same as scratching and urinating somewhere at a road split, so, visual and scent markings are combined again.
Also, such unusual things are used by wolves during their grooming, for instance, after fat eating at a kill in a special spots.
Parental wolves bring such strange things to pups for their play in order to grow them strong and dexterous, that pups are getting in their struggling by seizing the toys from each other. Such a toy brings much competitive feeling in playing of pups and activate the play.
Subadult yearling wolves use these things, when they stay alone without parents, who left for denning and raising small pups. They use toys for hierarchy matter and to amuse themselves.
Interestingly, that similar features are representative for dogs.