 What's interesting, the human body is one of only a few mammals who do not make our own vitamin C. The other ones are guinea pigs, primates, and the fruit bat. When you look at the rest of the animals out there, you don't see cats and dogs and elephants and giraffes with high blood pressure. You don't see the cancers, the arthritis, the tiredness all the time. All those animals make their own vitamin C.