Our late Cocker Spaniel, Rufus, was a very sharp, intelligent dog.
Once by accident we had left him in the house and were gone too long. He knew that toileting on the run was wrong, so he used a cat box. The cats resented it, and would no longer use THAT cat box (we had five cat boxes). From then on, it was his, but that is besides the point BECAUSE no one taught him to use it in the first place. It was not learned behavior - he figured it out for himself.
Cats are soooo possessive.................