Ask HN: What is your favourite obscure or surprising fact?

94% of sexual activity in male Giraffes is homosexual.

http://en.wikipedia.org/wiki/Homosexual_behavior_in_animals

Light has no mass so it does not experience time. Everything happens instantly for it.

While it takes us 10 years to wait for light to travel 10 light-years, the light takes no time at all.

This explains it perfectly:

http://www.askamathematician.com/2011/07/q-does-light-experi...

A lump of lead will float in a pool of mercury.

Ligers do exist. Lions and Tigers can breed and when a male lion and a female tigress mate, it makes a Liger. The liger is the biggest feline ever and they are extremely massive! To really see how massive they are, you can see an adult liger in this video next to a man : http://www.youtube.com/watch?v=1zOWYj59BXI

http://en.wikipedia.org/wiki/Liger

A pickle (or Gherkin) is just a cucumber.

The brain is the most complicated object known to man. The number of possible unique thoughts by any brain is greater than the number of molecules in the universe.