Human Penises Used to Have Spikes, Wait, Used to Have?


Researchers have discovered the molecular workings that caused human penises to evolve and shed their prickly spines, which chimps and some other animals still have to this day. Scientific American describes how Stanford scientists went through the DNA sequences that chimpanzees — but not humans — have and found that one contained instructions for penile spines and sensory whiskers. Or, as Jay Leno will probably say tonight, “You think dating is a pain now, ladies?”

Here’s the “why” and the “how”:

It has long been believed that humans evolved smooth penises as a result of adopting a more monogamous reproductive strategy than their early human ancestors. Those ancestors may have used penile spines to remove the sperm of competitors when they mated with females. However, exactly how this change came about is not known.

The researchers did not set out to study penile spines. Rather, they were looking for chunks of DNA that had been lost from the human genome but not the chimp genome, so they could then try to pinpoint what those chunks did.

The researchers also found a sequence that worked as a sort of brain-growth “off switch.” This may explain why our brains are more advanced than our ape counterparts, and why humans have been able to create over five different flavors of Mountain Dew.

You may think that the discovery of how our brains have developed would trump the news about penis spikes, but clearly you don’t know what people want.

(People want to read about spiky penises.)