Certainly suggestive
and completely unexpected and as mentioned, a complete transition to a meat based
diet appears unlikely except perhaps not.
We already understand that the Bigfoot successfully hunts deer with
thrown stones and the giant sloth which has the claws converts meat into
maggots. The first strategy is tailored
made for a move into the savanna to simply follow the herds.
The other problem left
unaddressed is that this sedge diet requires a large gut system that we presently
have scant evidence of. It is actually
easier go accept that this reflects the transition from a forest based
vegetable and fruit diet to a hunting diet.
This would also naturally transition into fish based coastal sub-populations.
Forest to ocean is
actually too great a leap without a transition step and this appears to be it.
Scientists 'Surprised'
to Discover Very Early Ancestors Survived On Tropical Plants, New Study
Suggests
New
research suggests that between three million and 3.5 million years ago, the
diet of our very early ancestors in central Africa is likely to have consisted
mainly of tropical grasses and sedges. (Credit: © timur1970 / Fotolia)
Dec.
14, 2012 — Researchers involved in a new study led by Oxford University
have found that between three million and 3.5 million years ago, the diet of
our very early ancestors in central Africa is likely to have consisted mainly
of tropical grasses and sedges. The findings are published in the early online
edition ofProceedings of the National Academy of Sciences.
An
international research team extracted information from the fossilised teeth of
three Australopithecus bahrelghazaliindividuals -- the first early
hominins excavated at two sites in Chad. Professor Julia Lee-Thorp from Oxford
University with researchers from Chad, France and the US analysed the carbon
isotope ratios in the teeth and found the signature of a diet rich in foods
derived from C4 plants.
Professor
Lee-Thorp, a specialist in isotopic analyses of fossil tooth enamel, from the
Research Laboratory for Archaeology and the History of Art, said: "We
found evidence suggesting that early hominins, in central Africa at least, ate
a diet mainly composed of tropical grasses and sedges. No African great apes,
including chimpanzees, eat this type of food despite the fact it grows in
abundance in tropical and subtropical regions. The only notable exception is
the savannah baboon which still forages for these types of plants today. We
were surprised to discover that early hominins appear to have consumed more
than even the baboons."
The
research paper suggests this discovery demonstrates how early hominins
experienced a shift in their diet relatively early, at least in Central Africa.
The finding is significant in signalling how early humans were able to survive
in open landscapes with few trees, rather than sticking only to types of
terrain containing many trees. This allowed them to move out of the earliest
ancestral forests or denser woodlands, and occupy and exploit new environments
much farther afield, says the study.
The
fossils of the three individuals, ranging between three million and 3.5 million
years old, originate from two sites in the Djurab desert. Today this is a dry, hyper-arid
environment near the ancient Bahr el Ghazal channel which links the southern
and northern Lake Chad sub-basins. However, in their paper the authors observe
that at the time when Australopithecus bahrelghazali roamed, the area
would have had reeds and sedges growing around a network of shallow lakes, with
floodplains and wooded grasslands beyond.
Previously,
it was widely believed that early human ancestors acquired tougher tooth
enamel, large grinding teeth and powerful muscles so they could eat foods like
hard nuts and seeds. This research finding suggests that the diet of early
hominins diverged from that of the standard great ape at a much earlier stage.
The authors argue that it is unlikely that the hominins would have eaten the
leaves of the tropical grasses as they would have been too abrasive and tough
to break down and digest. Instead, they suggest that these early hominins may
have relied on the roots, corms and bulbs at the base of the plant.
Professor
Lee-Thorp said: "Based on our carbon isotope data we can't exclude the
possibility that the hominins' diets may have included animals that in turn ate
the tropical grasses. But as neither humans nor other primates have diets rich
in animal food, and of course the hominins are not equipped as carnivores are
with sharp teeth, we can assume that they ate the tropical grasses and the
sedges directly."
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