Early hominids ate just about everything

Early hominids ate just about everything
Very few people today live a true hunter-gatherer lifestyle – and Paleo diets likely oversimplify what would have been on the table many millennia ago. Credit: Thiery, CC BY-NC

Reconstructions of human evolution are prone to simple, overly-tidy scenarios. Our ancestors, for example, stood on two legs to look over tall grass, or began to speak because, well, they finally had something to say. Like much of our understanding of early hominid behavior, the imagined diet of our ancestors has also been over-simplified.

Take the trendy Paleo Diet which draws inspiration from how people lived during the Paleolithic or Stone Age that ran from roughly 2.6 million to 10,000 years ago. It encourages practitioners to give up the fruits of modern culinary progress – such as dairy, agricultural products and processed foods – and start living a pseudo-hunter-gatherer lifestyle, something like Lon Chaney Jr. in the film One Million BC. Adherents recommend a very specific "ancestral" menu, replete with certain percentages of energy from carbohydrates, proteins and fats, and suggested levels of physical activity. These prescriptions are drawn mainly from observations of modern humans who live at least a partial hunter-gatherer existence.

But from a scientific standpoint, these kinds of simple characterizations of our ancestors' behavior generally don't add up. Recently, fellow anthropologist C. Owen Lovejoy and I took a close look at this crucial question in human behavioral evolution: the origins of hominid diet. We focused on the earliest phase of hominid evolution from roughly 6 to 1.6 million years ago, both before and after the first use of modified stone tools. This time frame includes, in order of appearance, the hominids Ardipithecus and Australopithecus, and the earliest members of our own genus, the comparatively brainy Homo. None of these were modern humans, which appeared much later, but rather our distant forerunners.

We examined the fossil, chemical and archaeological evidence, and also closely considered the foraging behavior of living animals. Why is this crucial? Observing animals in nature for even an hour will provide a ready answer: almost all of what an organism does on a daily basis is simply related to staying alive; that includes activities such as feeding, avoiding predators and setting itself up to reproduce. That's the evolutionary way.

What did our ancestors actually eat? In some cases, researchers can enlist modern technology to examine the question. Researchers study the chemical makeup of fossil dental enamel to figure out relative amounts of foods the hominid ate derived from woody plants (or the animals that ate them) versus open country plants. Other scientists look in ancient tooth tartar for bits of silica from plants that can be identified to type – for example, fruit from a particular plant family. Others examine the small butchering marks made on animal bones by stone tools. Researchers have found, for example, that hominids even 2.6 million years ago were eating the meat and bone marrow of antelopes; whether they were hunted or scavenged is hotly debated.

Such techniques are informative, but ultimately give only a hazy picture of diet. They provide good evidence that plants' underground storage organs (such as tubers), sedges, fruits, invertebrate and vertebrate animals, leaves and bark were all on the menu for at least some . But they don't give us information about the relative importance of various foods. And since these foods are all eaten at least occasionally by living monkeys and apes, these techniques don't explain what sets hominids apart from other primates.

Early hominids ate just about everything
Scraping ancient teeth for clues about diet.

So how should we proceed? As my colleague Lovejoy says, to reconstruct hominid evolution, you need to take the rules that apply to beavers and use them to make a human. In other words, you must look at the "rules" for foraging. We aren't the first researchers to have dabbled in this. As long ago as 1953, anthropologists George Bartholomew and Joseph Birdsell attempted to characterize the ecology of early hominids by applying general biological principles.

Happily, ecologists have long been compiling these rules in an area of research dubbed optimal foraging theory (OFT). OFT uses simple mathematical models to predict how certain animals would forage in a given circumstance. For instance, given a set of potential foods of estimated energetic value, abundance and handling time (how long it takes to acquire and consume), one classic OFT model calculates which resources should be eaten and which ones should be passed over. One prediction—sort of a "golden rule" of foraging—is that when profitable foods (those high in energy and low in handling time) are abundant, an animal should specialize on them, but when they are scarce, an animal should broaden its diet.

Data from living organisms as disparate as insects and modern humans generally fall in line with such predictions. In the Nepal Himalaya, for example, high-altitude gray langur monkeys eschew leathery mature evergreen leaves and certain types of roots and bark—all calorie-deficient and high in fibers and handling time—during most of the year. But in the barren winter, when better foodstuffs are rare or unavailable, they'll greedily devour them.

In another more controlled study, when differing quantities of almonds in or out of the shell are buried in view of chimpanzees, they later recover larger quantities (more energy), those physically closer (less pursuit time), and those without shells (less processing time) before smaller, more distant, or "with-shell" nuts. This suggests that at least some animals can remember optimal foraging variables and utilize them even in cases where foods are distant and outside the range of immediate perception. Both of these studies support key predictions from OFT.

If one could estimate the variables important to foraging, one could potentially predict the diet of particular hominids that lived in the distant past. It's a daunting proposition, but this human evolution business was never meant to be easy. The OFT approach forces researchers to learn how and why animals exploit particular resources, which leads to more thoughtful considerations of early hominid ecology. A smattering of scientists have utilized OFT with success, most notably in archaeological treatments of comparatively recent , such as Neandertals and anatomically modern humans.

Early hominids ate just about everything
Himalayan gray langurs in early fall when the living is comparatively easy and there’s no need to fall back on ‘nonprofitable’ foods. Credit: Ken Sayers, CC BY-NC-ND

But a few brave souls have delved into more remote human dietary history. One team, for example, utilized OFT, modern analogue habitats, and evidence from the fossil record, to estimate the predicted optimal diet of Australopithecus boisei. That's the famed "Nutcracker Man" that lived in East Africa close to 2 million years ago. The research suggests a wide range of potential foods, greatly varying movement patterns – based on characteristics such as habitat or use of digging sticks—and the seasonal importance of certain resources, such as roots and tubers, for meeting estimated caloric requirements.

Researchers Tom Hatley and John Kappelman noted in 1980 that hominids have bunodont – low, with rounded cusps – back teeth that show much in common with bears and pigs. If you've watched these animals forage, you know they'll eat just about anything: tubers, fruits, leafy materials and twigs, invertebrates, honey and vertebrate animals, whether scavenged or hunted. The percentage contribution of each food type to the diet will depend (you guessed it) on the energetic value of specific foods in specific habitats, at specific times of year. Evidence from the entirety of suggests that our ancestors, and even we as , are just as omnivorous.

Early hominids ate just about everything
A skull of so-called ‘Nutcracker Man’ – hungry for anything. Credit: North Carolina School of Science and Mathematics, CC BY-NC-SA

And the idea that our more ancient ancestors were great hunters is likely off the mark, as bipedality—at least before the advance of sophisticated cognition and technology—is a mighty poor way to chase game. Even more so than bears and pigs, our mobility is limited. The anthropologist Bruce Latimer has pointed out that the fastest human being on the planet can't catch up to your average rabbit. Another reason to be opportunistic about food.

Simple characterizations of hominid ecology are divorced from the actual, and wonderful, complexity of our shared history. The recent addition of pastoral and agricultural products to many modern human diets—for which we have rapidly evolved physiological adaptations —is but one extension of an ancient imperative. Hominids didn't spread first across Africa, and then the entire globe, by utilizing just one foraging strategy or sticking to a precise mix of carbohydrates, proteins and fats. We did it by being ever so flexible, both socially and ecologically, and always searching for the greener grass (metaphorically), or riper fruit (literally).

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More holistic approach needed when studying the diets of our ancestors

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Feb 17, 2015
"Early hominids ate just about everything" and still do

Feb 17, 2015
I'm sorry, but what was the conclusion of this study? That ancient hominids ate whatever they could get their hands on? Oh. I thought they ate truffles and caviar exclusively. Thanks for enlightening me.

Feb 17, 2015
They stil do!!

Feb 17, 2015
You also need to know how far they foraged for food. Their feet were much stronger than modern humans as they still climbed trees to find food and they still had to follow animals for miles in their hunt.I did some work in making my foot stronger by doing toe crunches and extensions and my foot went to how a person who never wore shoes.at present I can push/pull 45lbs with my toes and i am a much faster runner for it

Feb 17, 2015
Food odors cause the de novo creation of olfactory receptor genes. The creation of new genes is the holy grail of molecular biology.

Nutrient-dependent/pheromone-controlled adaptive evolution: a model. http://www.ncbi.n...24693353

Light-induced amino acid substitutions link cell type differentiation from plants to algae and to nutrient-dependent RNA-mediated cell type differentiation in species from microbes to man via fixation of the amino acids in the DNA of organized genomes. Fixation occurs via the nutrient-dependent pheromone-controlled physiology of reproduction.

One nutrient-dependent amino acid substitution in the circulating red blood cells of other primates can differentiate all cell types. That was reported more than 40 years ago.
"...the so-called alpha chains of hemoglobin have identical sequences of amino acids in man and the chimpanzee, but they differ in a single amino acid (out of 141) in the gorilla."

Feb 18, 2015
It's obvious humans evolved as omnivores.

Feb 19, 2015
Edgar Owen, is one of the antagonists that helped get me banned from commenting to the evolutionary psychology yahoo group moderated by Robert Karl Stonjek.

He just posted this comment to the group.

This of course confirms what I've proposed here on a number of occasions. The actual Paleo diet included plenty of insects, half spoiled meat and many suboptimal nutrition sources. And in many locations included frequent periods of want and starvation. Certainly not the golden age some claim it to have been.

The development of agriculture was a huge step forward and was what allowed human populations to exponentially increase...

Obviously, we will see much more of this "knew it all along" nonsense from the biologically uninformed science idiots who still don't realize that nutrient uptake is required but also the pheromone-controlled physiology of reproduction that enables fixation of the nutrient-dependent amino acid substitutions that repair DNA damage.

Feb 19, 2015
The moderator/owner of the evolutionary psychology group previously wrote:
That you languish in the opinion/discussion forum is, by far, the biggest admission of the weakness of your overall position.

I was about to provide examples to show the difference between 1) what a spontaneous change in a single base pair does, and 2) what a nutrient-dependent pheromone-controlled change in single base pair does.

I posted the information to my blog site, instead -- after commenting here about being banned from the group.


See also my posts on RNA-mediated events that link nutrient-dependent pheromone-controlled cell type differentiation in species from microbes to humans via their biophysically constrained chemistry of protein folding and conserved molecular mechanisms:

Search Results for: RNA-mediated

Feb 19, 2015
Early hominids did not eat about everything: the different hominid species had each their own dietary preferences, e.g.
-East-African australopiths were predominantly herbivorous: molar enamel micro-wear of A.afarensis shows polishing by wet plants (P-F.Puech), possibly comparable to the AHV (aquatic herbaceous vegetation) eaten by lowland gorillas in forest swamps & wetlands, but A.boisei had thicker enamel & broader cheek-teeth, probably for more abrasive foods, e.g. papyrus sedges (isotopic & paleo-environmental data), google "aquarboreal".
-South-African australopiths probably evolved in parallel, but were more omnivorous.
-Pleistocene archaic Homo OTOH did not run over open plains, but dispersed along coasts & rivers as far as Java 1.8 Ma, beach-combing, diving & wading bipedally for littoral, shallow aquatic & waterside animal & plant foods: shellfish, seafood, waterside herbs, nuts & fruits, drowned ungulates, stranded whales etc., google "researchGate marc verhaegen".

Feb 19, 2015
AFAWK, hominids rarely ate bone marrow: hyenas & vultures were a lot faster & too dangerous. We never lived on open savannas: we need too much water & sodium (scarce in savannas), we are much too fat & slow & broadly built, our furless skin is vulnerable to sunbeams, thorns, claws & canine teeth, our kidneys need a lot of water, etc. Homo's drastic brain expansion is best explained by dispersing along (sub)tropical & later also temperate African & Eurasian coasts & rivers: seafood is extremely rich in brain-specific nutrients such as DHA. A coastal-riverside Pleistocene dispersal also explains the thick bones of archaic Homo, their flat & long skulls, smaller dentition, elaborate stone tool use, dorso-ventrally flattened femora, broad body build (skull, thorax, pelvis), their "fast" global diaspora (1.8 Ma already at least as far as Aïn-Hanech in Algeria, Dmanisi in Georgia, Turkana in the Rift, Mojokerto on Java) etc., e.g. google "independent. academia. edu/marcverhaegen".

Feb 19, 2015
Thanks for including the link from quantum physics to DHA and quantum biology, which extends to quantum consciousness.

A quantum theory for the irreplaceable role of docosahexaenoic acid in neural cell signalling throughout evolution http://www.ncbi.n...23206328

Elaine Morgan claimed we evolved from aquatic apes

What differentiates your claims from hers?

From Dobzhansky's: "...the so-called alpha chains of hemoglobin have identical sequences of amino acids in man and the chimpanzee, but they differ in a single amino acid (out of 141) in the gorilla." http://www.jstor..../4444260

What differentiates your claims from mine: Nutrient-dependent / Pheromone-controlled adaptive evolution: (a mammalian model of thermodynamics and organism-level thermoregulation)

Feb 20, 2015
Re: marc verhaegen's mention of Dmanisi in Georgia

See: http://comments.s....1238484

Excerpt: "Even the location where skull 5 was found will be only mildly surprising to readers of Greg Bear's science fiction novels: Darwin's Radio and Darwin's Children. His story about the evolution of a new species of human began in Georgia, like the story of skull 5."

I hope that Dr. Verhaegen will respond to my question about the difference between his model and that of Elaine Morgan's "Aquatic Ape." Serious scientists should not continue to work in isolation from other serious scientists.

That lets science fiction authors make a more realistic case than those who study how ecological variation leads to ecological adaptations via nutrient-uptake and pheromone-controlled reproduction in species from microbes to man.

Greg Bear, "When Genes Go Walkabout" https://www.youtu...NcMR_-RU

Feb 20, 2015
JVK, see refs above, google
-researchGate marc verhaegen
-independent. academia. edu/marcverhaegen
Recent papers:
-The aquatic ape evolves: common misconceptions and unproven assumptions about the so-called Aquatic Ape Hypothesis 2013 Hum.Evol.28:237-266
-with Stephen Munro (discovered the 0.5-Ma Javan shellfish engravings, Joordens etc.2014 Nature) Pachyosteosclerosis suggests archaic Homo frequently collected sessile littoral foods 2011 HOMO J.compar.hum.Biol.62:237-247
-S.Munro. Molluscs as ecological indicators in palaeoanthropological contexts 2010 PhD.thesis Austr.Univ
-Mario Vaneechoutte etc. Reply to John Langdon's review of the eBook: Was Man more aquatic in the past? 2013 HOMO J.compar.hum.Biol.63:496-503
Elaine Morgan thought AAT began with wading c.6 Ma, causing the Homo/Pan split.
But in our view
-Mio-Pliocene hominoids lived in swamp forests & wetlands, google: aquarboreal
-Pleistocene Homo <2 Ma followed Eurasian & African coasts & rivers.

Feb 20, 2015
Thanks. I'd seen them. Could you provide a synopsis of how your claims differ from Elaine Morgan's or from mine?

The role of "Molluscs as ecological indicators in palaeoanthropological contexts" is interesting, since they also appear to link entropic elasticity to cell type differentiation. The problem is that none of us has time to become familiar with everything others have published in different disciplines.

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