They say that one of the things that sets us apart from animals is our ability to use tools, be they opportunistic uses such as picking up a rock and using it as a hammer or created tools. In the animal world it is only really identified as ourselves and the Chimpanzee who fashion tools for use.
I think humans need to broaden their definition and realise that animals are more intelligent that we give them credit for. Take the satin bower bird. The male of which actively seeks out and collects objects of a particular colour to adorn its nest with the express intention of attracting mates. This is surely an example of tool use for decoration.
The latest discovery is an octopus who uses coconut shells to hide in. But it’s not opportunistic, as in it doesn’t just find the half-shell where it is and climb under it. The veined octopus of Indonesia actively finds and carries coconut shells as part of a defensive procedure. It’s quite funny to watch the animals scurry along the bottom of the ocean coconut shell held under its body. And it’s also amazing.http://www.youtube.com/watch?v=1DoWdHOtlrk
Find out more about the Veined Octopus on Wikipedia.