dog strange eating habits

Question
I have a 13 year old cross collie, I would say for the majority of his life he has a strange eating habit from eat paper tissues, cotton wool, make-up sponges, earth stones and so on. Any idea what gives him these strange urges to eat such item.

Answer
I am not sure there is a good explanation for that common behavior.  I am only surprised he is still doing so at 13.  It is a major problem with young Labs and Goldens.  Just try to keep as much as possible away from him.  The dog guide school clinic has a display of things they have had to remove from dogs.

Perhaps I didn't fully answer your question, but I hope my answer helps.