It seems that there were these 3 pregnant Indian Squaws, all due to give birth at about the same time. The first squaw gave birth to a boy, and the birthing was done on a deer hide. The 2nd also gave birth to a boy, but this was done on a bear hide. And, the third had twins, two boys, and she did this on a hippopotamus hide. This means that the sons of the squaw on the hippopotamus hide is equal to the sons of the squaws on the other two hides.