Last one before I head off to work (or you guys lynch me )

An Indian chief had three wives, all of which gave birth.
The first had a boy and the chief built her a teepee of deer hide.
The second also had a boy and the chief built her a teepee of antelope hide.
When the third gave birth, the chief built her a two story teepee, made out of a hippopotamus hide.
The chief then challenged the tribe to guess what had occurred. Many tried, unsuccessfully.
Finally, one young brave declared that the third wife had given birth to twin boys.
'Correct,' said the chief. 'How did you figure it out?'
The warrior answered, 'It's elementary. The value of the squaw of the hippopotamus is equal to the sons of the squaws of the other two hides.'