However, because vitamin C is so common in fruits, animals that eat lots of fruit don’t really need to make it themselves. So when a frugivore (fruit eating animal) has a genetic mutation that means they can’t make vitamin C anymore, evolution often doesn’t notice, and the animal survives to spread the mutation throughout its species. Because this ancient primate was living in the jungle and eating mainly fruit, this mutation went unnoticed, and the primate was able to pass on his genes and eventually a whole host of different primate species were unable to make their own vitamin C.