Cat

Cats purr at 25-150 Hz, and 25-50 Hz happens to match low-frequency vibration therapy used to boost bone density and speed fracture healing. This overlap inspired the hypothesis that cats, who purr even when hurt, may be self-medicating with sound.

During the Cold War, the CIA spent about $20 million on "Acoustic Kitty," implanting a microphone, battery and antenna inside a live cat to spy on Soviet diplomats. In its first field test, a taxi hit the cat near the Soviet Embassy. The CIA shut it down as impractical.

Cats cannot properly taste sweetness. A sweet receptor normally works as a pair of proteins, but in cats the TAS1R2 gene is a broken pseudogene, so they cannot make a functional sweet-taste receptor.

Members of the cat family cannot hold water in their mouths because their cheeks are not fully sealed. Instead, they dip their barb-covered tongues into water, creating a momentary water column, then snap their jaws shut to bite off the column.

The Chinese zodiac animals vary by country. What is a dragon in Korea is a seagull in India, a whale in Iran, and a snail in Central Asia. In Vietnam, the "rabbit" position is held by a cat.