Tuesday, October 10, 2017

Cavemen Rule, Part IV: Homo habilis

Cavemen Rule, Part IV: Homo habilis

So, last week (ed.: month!) we talked about Australopithecus, and how over time this genus became more and more gracile, relying on tools and problem-solving to get access to a variety of food sources.  We even have an assemblage of stone tools that appear to have been manufactured by Australopithecus, and the astonishing Makapansgat pebble demonstrates even a flicker of abstract thought.  As time passed, some of these creatures became distinct enough that we begin to refer to them as members of the genus Homo, or “man”, under the premise that by this point, they had become more like us than like Australopithecus.  The very oldest find that could be reasonably argued to have Homo traits is the unassumingly named “LD-350-1” mandible, found in Ethiopia and dating from around 2.7 to 2.8 MYA:

So, what were these first Homo creatures like?  Well, at the beginning, they probably weren’t that different from their australopithecine brethren.  They have been traditionally referred to as Homo habilis by science, traditionally translated “handy man”.  Here’s what they looked like:

                There are a lot of reconstructions out there, of course, but I’m inclined in my layman’s opinion to favor the ones that look more ape-like, since these guys were very much a transitional species.  It’s also important to note that by this time, human ancestors probably hadn’t lost their body hair yet, although the process may have been underway(1).

                In fact, habilis displays so many archaic, australopithecine features that some scientists are arguing for a new classification to what they would call Australopithecus habilis(2).  But I don’t really know enough about this debate to have an opinion on it.

                Let’s talk about what the behavior of these creatures may have been like.  A good place to start may be the toolkit they left behind for us.  Nowadays, we refer to the tools made by Homo habilis as the Oldowan industry, named after Tanzania’s Olduvai Gorge.  I remember it like this: the OLDowan industry is really OLD!  Dohohoho!  


These are the oldest manufactured items that we have ever found; it cannot be repeated enough that, an unimaginably long time ago, our ancestors held these very stones in their hands and fashioned them into crude choppers and scrapers:

                Here we see a typical Oldowan chopper tool.  As we can see, there’s not a lot of complexity to it—it’s really just a rock that they hit with another rock until they had a sharp edge to work with.  Some background knowledge was necessary—the toolmakers needed to know where, and at what angle, to strike in order to produce a sharp edge.  Regardless, as we can see, there is a haphazard quality to these tools, and they were made with a kind of strict practicality in mind.  These objects are functional, not aesthetic, and from this I infer that their makers probably didn’t give a whole lot of thought to things beyond simple survival.  When I look at these simple tools, I cannot imagine that, finding myself among a band of H. habilis, I would find myself feeling much more at home than among a band of australopithicines.

                But even at this stage, there may have been some behavioral quality to these guys that set them apart from Australopithecus.  Their brains were about 50% larger(2), and while that doesn’t necessarily mean they were smarter—however “smart” may be defined—they certainly could have been.  This difference in cognitive ability could have manifested itself as more “pickiness” in selecting rocks for use as tools, or as more of a tendency toward teamwork in accomplishing tasks, as opposed to intra-group competition.  Food could have been obtained in more innovative ways, such as by waiting for predators to bring down an animal, scaring the predators away, and taking the meat for themselves.  On the other hand, this competition with predators over carcasses may also explain why habilis, in contrast to later humans, was a “staple in the diet of larger predatory animals”(3).  To me this suggests that they still had a way to go in terms of outsmarting their predators. 

If I were given the opportunity to observe a living habilis community, I would do so more as a primatologist than as an anthropologist.  Their behavior certainly would have been more humanlike than that of chimpanzees, but probably not by much.  It’s doubtful that one of us could sit down with a habilis and interact with it in the same way we interact with one another, even by a long shot.

Safety would be a concern, too.  Primatologists are very rigorously trained in interpreting great ape behavior before going into the field, because great apes can be unpredictable and dangerous.  Behaviorally modern humans are the product of millions of years of social evolution that allows us to be around people we don’t know without killing each other.  Habilis was only beginning this process.

                One very important issue regarding habilis is where exactly they fit in the story of human evolution.  Were they our direct ancestors, or were they part of an evolutionary line that branched off from ours earlier on?  If they are not our ancestors, did they have descendants who were distinct from us?  The first question cannot be answered now, but in recent years, incredible discoveries have been made that seem to imply that habilis founded a separate Homo lineage, developing entirely independently of our own, that persisted to an astonishingly recent date.  I don’t want to go any further, because that would ruin the awesome twist ending, but stay tuned, because it’s gonna blow your mind.

                So that’s it for Homo habilis.  Next time we’re going to talk about Homo ergaster and Homo erectus, two species that would ultimately give rise to our lineage.  We’re even going to look at a couple specimens of these guys and, amazingly, reconstruct what these individuals’ lives must have been like.  See you next time!

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