Ah yes, I've seen a similar demonstration on an Animal Planet or National Geographic program, where the owner and dog gave a performance showcasing its vocabulary of over 100 items...
And when the owner mentioned the name of a new item that the dog never heard before, the dog went all over looking and sniffing at each of the items he recognized, then finally picked up the one that he has never seen before!
Even if animals don't comprehend human language, they still have their own basic notions of logic, deductions and emotions, just like little kids - cute, innocent and naive hehe... I really can't stand those people that mistreat animals because they are "just animals".