My fave out of all of them is #8, the ever inventive octopus:
An octopus that uses coconut shells as portable armor is the latest addition to a growing list of tool users in the animal kingdom. The veined octopus apparently can stack coconut shell halves that people discarded just as one might pile bowls, sits atop them, makes its eight arms rigid like stilts, and then ambles the entire heap across the seafloor, using them for shelter later when needed. These new findings are apparently the first reported instance of an invertebrate that acquires tools for later use.
