In a recent find, archaeologists have uncovered evidence of early humans with small brains
supporting an elderly human with no teeth. This goes against the idea that these social
behaviours require large brains and would only happen in more evolved humans. Let dive
in and find out more.
One of the most important sites in the story of human evolution can be found close to the
Georgian capital Tbilisi. Near the twisting river Mashevera, with forests, fields and
black basalt hills stretching for miles there is a site which is barely 10 acres. It is
dominated by medieval ruins and a small working monastery where monks tend hives of honeybees.
Despite these buildings the surroundings have not changed much in the last 2 millions years.
If we wind back the clock then this area was a biodiversity hotspot and was home to a unique
assemblage of carnivores, including several big cat species, from Africa, Europe, and
Asia.
Previously we have looked at the story of new finds from Crete which showed that the
idea of humans evolving and then migrating out of Africa was wrong. These finds in Crete
seemed to indicate that humans were already present in Europe right at the beginning of
their evolutionary branch.
In Georgia the finds also seem to support this idea with more evidence of hominins outside
of Africa. Since the late 1980’s this site has been a treasure trove of discoveries.
In a new piece of research a team led by the University of Zurich scientist have analysed
the likely brain organization in these early hominins and it upends a long held belief
that quintessentially human behaviours require big, complex brains.
The hominins they uncovered had surprisingly primitive, ape-like brains and yet they were
able to produce a variety of tools, and exploit animal resources. More remarkable is that
it appeared as if their society also took great care of their elderly. They discovered
the skull which belonged to an elderly, toothless individual who would have been unable to eat
on their own. It is thought they did not have access to fire so could not cook their food.
So it would have been impossible for a toothless individual to survive. On top of this they
lived amongst what appears to be an extraordinary concentration of big carnivores.
This is really astounding. This provides a completely new perspective on what these behaviours
mean in terms of brain evolution.
The fossils in this region stand apart for a number of reasons. The site itself is in
a transitional region between Georgia’s wet humid west and its arid east. It sits
along a migratory path for animals that summer at the higher elevations in the mountains
to the north. The area itself sits at the confluence of two rivers with narrow deep
valleys which naturally concentrate the animals.
More than 10,000 animal bones have been from the site and these include at least 50 different
mammal species. So unique is the combinations of areas that these animals include a very
fascinating mix that seems to spread 3 continents. These include rhinoceros, elephants, deer,
ostriches, and horses. The carnivores include coyote sized wolves, two species of saber
tooth cats, lynx, bears, giant hyenas, a lion sized jaguar and a giant cheetah.
The plants and trees also paint a very strange picture. It consists of a patchwork of forest
and grassland. This means that there is such diversity that there is something there for
everybody.
This paradise seems to have been a very short lived event. All the fossil remains they have
discovered have come from a single layer in the rock which they date to 1.77 million years
ago. It is sandwiched between two layers of volcanic ash. This region's diversity may
therefore have only existed for less than 10,000 years and possibly as short as only
a few hundred years. It was then buried quickly but gently by ashfall from regional volcanoes
that preserved the strange history.
There are a number of elements that raise some rather interesting questions from this
article. Firstly the fact that no other fossils are found in this region pre or post dating
this event is rather curious. It is thought that the region dried out after the event,
meaning an end to this paradise, less animals and conditions which do not favour the formation
of fossils. But what about before this time? If this area only existed for such a short
period of time why was it so inhospitable prior to the first volcanic event? It once
more highlights the problems we face in reconstructing our history. There is no single area place
that contains all the strata in order. I have previously discussed the problems with dating
the strata and making assumptions about how a particular strata fits in with what they
assume is a global record. There are many problems with the dating methods they use
that I have also previously touched upon.
What this site does present is a very interesting sandwich between two catastrophic events that
seemed to have created a perfect paradise for only a very short period of time.
The number and variety of animals found here is remarkable and could indeed be explained
by the fact that at the time it bordered both wet and dry areas. It does however also remind
me of the Earth in Upheaval series and the variety of animals again from such differing
climates that seems to have been found together across the caves of Europe, Alaska and Siberia.
The next question is how and why these early humans could support an elderly person with
no teeth? The current assumption is that they only ate raw meat and were predominantly scavengers
rather than hunters. Some of the animal bones show signs that they were butchered using
stone tools. Some of the hominin bones also show signs of gnaw marks indicating that they
were also sometimes on the menu for the animals that lived there. Eating without teeth is
really not an easy task, add into this mix the fact that they think they only ate raw
meat you have to ask how exactly these early humans supported this individual. What was
their motivation to do this? It was assumed that these sorts of quintessential behaviours
would only happen with larger brained humans. This once more raises the question about our
understanding of what exactly intelligence is and how it relates to the brain and its
size.
What triggered the event prior and just after this period? We know that the area was covered
in ash so this has to have come from volcanic activity. From Bruce Leybourne’s work there
is a clear connection with the Earth’s electric circuit and volcanic activity. The question
here would be why was there a long enough period of time for this paradise to spring
up only to be destroyed a few thousand years later and then to never return again in the
same way afterwards?