Mice

Have you ever heard the phrase "quiet as a mouse"? Come to find out, it's far from true. Mice use a variety of sounds to communicate, most of which are inaudible to the human ear. Male mice will even "sing" to attract a mate -- the only non-human "singing" species, other than bats and whales. When put together, male mice will even match pitch with each other.

They also use other methods of communication. Mice use facial expressions to emote, just like humans, as well as their sense of smell. In fact, a mouse's smell is so powerful, Israeli scientists are training them to detect trace amounts of explosive materials, narcotics, even large amounts of money. The little rodents are more accurate than x-ray machines, full body scanners, and even more accurate than bomb-sniffing dogs.