I think one of the uniting characteristics of the topics that interest me is that they all have something to do with altering our perception of the commonplace reality around us.
This capacity for (in writer Kathryn Schulz's words) "seeing the world as it isn't" led me to writing fiction, but also to the weird and counterintuitive bits of quantum physics, the expansive vision of astronomy, and the fields studying that which no longer exists -- history, archaeology, paleontology. It's this last one that brings this whole topic up, with a pair of discoveries revealed this week that leave me kind of awestruck.
The first, which came my way from my buddy Andrew Butters over at the wonderful blog Potato Chip Math, is about the discovery in South Africa of a two-million-year-old skull of Paranthropus robustus, a hominin considered a "cousin species" that coexisted with our direct ancestor species Homo erectus.
The find is remarkable from a number of perspectives, not least that a complete skull of any hominin is pretty unusual. "Most of the fossil record is just a single tooth here and there so to have something like this is very rare, very lucky," said Angeline Leece, who participated in the research. She added an evocative description of what the world was like when the owner of this skull was still alive and loping around on the African savanna. "These two vastly different species, Homo erectus with their relatively large brains and small teeth, and Paranthropus robustus with their relatively large teeth and small brains, represent divergent evolutionary experiments," Leece said. "Through time, Paranthropus robustus likely evolved to generate and withstand higher forces produced during biting and chewing food that was hard or mechanically challenging to process with their jaws and teeth — such as tubers. Future research will clarify whether environmental changes placed populations under dietary stress and how that impacted human evolution."
It's fascinating to imagine what the world was like to these creatures, during a time when there were several intelligent hominin species coexisting. I remember my evolutionary biology professor making that point; a lot of our attitude that species are these hard-and-fast little cubbyholes comes from the fact that we have no near relatives still alive. Much more common in the natural world are groups of closely-related species all competing and coexisting.
But it's still a little hard to picture wandering around the place and seeing other human-like, but not-quite-human, animals out there doing their thing.
It also bears keeping in mind that the other animal species they'd have been around weren't like the ones today, either. This point was driven home by the second discovery revealed this week, of a twelve-thousand-year-old frieze of cliffside paintings in Cerro Azul, Colombia, that show not only the usual assemblage of South American animals -- snakes, alligators, turtles, bats, monkeys, porcupines -- but mastodons, giant sloths, camelids, and some sort of three-toed ungulate with a trunk."These really are incredible images, produced by the earliest people to live in western Amazonia," said Mark Robinson, an archaeologist at the University of Exeter, who participated in the study. "The paintings give a vivid and exciting glimpse in to the lives of these communities. It is unbelievable to us today to think they lived among, and hunted, giant herbivores, some which were the size of a small car."
"These rock paintings are spectacular evidence of how humans reconstructed the land, and how they hunted, farmed and fished," said archaeologist José Iriarte, also of the University of Exeter. "It is likely art was a powerful part of culture and a way for people to connect socially. The pictures show how people would have lived amongst giant, now extinct, animals, which they hunted."