Rats breed fast, 2 rats can create over 1 million relatives in just 18 months
Cows and horses sleep while standing up.
Because natural gas doesn't have an odour, strong smells are added by humans so leaks can be detected.
The only rock that can floats in water is pumice.
Just because a snake has its eyes closed, don't think it's not still looking at you, they can see through their eyelids.
Sound moves 4 times faster through water than air.
While adults blink around 10 times a minute, infants blink only once or twice.
Mercury is the only metal in liquid form at room temperature.
Olympic gold medals look like gold but they're made mostly of silver.
Uranus is the only planet that rotates on its side (like a barrel).