The key difference between human beings and Neanderthals is how we consume and expend energy. It goes a long way toward explaining why we survived to the modern era while our — literal — kissing cousins died out.
That’s one of the interesting takeaways from a long article by Vox’s Brain Resnick exploring the inter-species sex lives of Homo sapiens and Homo neanderthalensis.
(Every living person not of exclusively African descent has some Neanderthal ancestry. It appears Neanderthals never made it to Africa.)
Resnick spoke to Bernard Wood, a paleoanthropologist at George Washington University. Here’s the bit of their conversation that stuck out to me:
“They probably needed about another 600 or 700 calories a day more than a modern human” to feed their hardier bodies, [Wood] explains — great in times of plenty but catastrophic in a famine. They were the gas-guzzling pickup truck of the hominids. We were the smart car.
That goes a ways toward explaining why our species of human out-competed Neanderthals, even as we mated with them.
It’s unclear how smart or social Neanderthals were, but we know they never formed the kinds of large, aggressive bands that Homo sapiens did. They were squatter than us, and bulkier, with wide bones and short foreheads. We also know their numbers dwindled, and then they disappeared around 40,000 years ago.
Wood’s suggestion, that Neanderthals were simply not energy-efficient enough to survive periods of scarcity, is compelling. (Still, as he points out later, Neanderthals managed to survive for a million years, far longer than we have so far.)
To be clear: Wood doesn’t claim that this difference in caloric need is the complete explanation for Neanderthals’ demise, but he does conjure an intriguing image — a species that simply requires more resources than the world could always offer.