Pet dogs and elephants are the only animals that seem to instinctively understand human gesture.
14
The focusing muscles of the eyes move around 100,000 times a day. To give your leg muscles the same workout, you would need to walk 80km (50 miles) every day.
21
An unprotected human can survive up to 1.5 minutes in space with no permanent bodily damage.
82
A cow produces around 200,000 glasses of milk in her lifetime.
373
Mars had an oxygen-rich atmosphere around 4 billion years ago
13