Polite Dissent

SHIELD Scientist: We’re after the Homo habilis. We want the caveman.

SHIELD Scientist: The pre-man, regardless of his origin, is an evolutionary time capsule. He is from a time before cancer, before AIDS.

Homo habilis lived during the early Pleistocene, roughly 1.8 – 2.5 million years ago. It is entirely likely that they lived before AIDS (though there were probably equally nasty diseases back then). It is untrue to say that Homo habilis lived “before cancer”; they did not. The first documented evidence of cancer dates back to 300-350 million years ago, the time of the vertebrate fishes — long before the first dinosaurs appeared, let alone ancient man. The frequency of cancers seemed to increase as the number of land-dwelling vertebrates rose, and another increase in cancers occurs once humans* appeared on the scene. Overall, the incidence of cancer appears to be substantially lower in the prehistoric era than in the modern era. There are likely many reasons for this, including fewer environmental toxins, a shorter lifespan, poorer detection … and a significant selection bias (who is or isn’t likely to end up fossilized, which cancers do not show up in fossilized remains, etc. etc.).

*Admittedly, there have not been any cancers found in the Homo habilis skeletons available, but there aren’t a whole lot of them to begin with (and fossilized bones aren’t the easiest way to find cancers). The first documented “human” case of cancer dates to 1.5 million years ago (Homo erectus), but I think it would be foolish to believe that Homo habilis never experienced cancer when it had already been around for millions of years, since the first of the vertebrates.