Name: Was Eating Insects Key to Human Brain Evolution?
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Our ancient ancestor Australopithecus likely foraged for termite larvae using tools made from bone. This source of fat could have helped brain development and growth, anthropologists believe.

Insects may have provided humans' ancestors with key nutrients.

Was Eating Insects Key to Human Brain Evolution?

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Our ancient ancestor Australopithecus likely foraged for termite larvae using tools made from bone. This source of fat could have helped brain development and growth, anthropologists believe.

Insects may have provided humans' ancestors with key nutrients.

Ancient Worlds

Was Eating Insects Key to Human Brain Evolution?Published: November 2, 2021Narrator: Insects are clearly a great source of nourishment. And this is leading some researchers to ask, “Was an insect diet key to the evolution of the exceptional human brain?”Biological anthropologist Julie Lesnik is studying a puzzling chapter in the story of human evolution, a remarkable increase in the brain size of our ancient ancestor, Australopithecus.Australopithecus was a small foraging ape that roamed the African savanna from just over 4,000,000 years ago. But something big is going on with her brain.Julie Lesnik: From about 5,000,000 to up to 2,000,000 years ago, we have this brain size expansion of about 20 percent.Narrator: This is a substantial increase. Its cause remains an evolutionary mystery, but experts believe it probably took a special diet to support this larger brain.Lesnik: Brains are energetically expensive. And one thing they especially need are fatty acids. Our brains run on fat, and fat is a very rare resource, naturally, in our environment. So, what were they eating?Narrator: It’s possible Australopithecus obtained this fat by scavenging the bodies of larger animals, but Julie thinks there’s an alternative and more surprising explanation.Termite mounds pepper the African savanna. Their rock hard exterior protecting the fatty larvae within. Our cousin, the chimpanzee, forages for termites today using ingenuity and simple tools to penetrate the termite fortress.Lesnik: Chimpanzees can thread into that termite nest with a flexible probe made of either grass or a green branch, and the soldier caste bite on to the end of that tool. And then chimpanzees extract them from the mound and eat those termites right off that probe.Narrator: This technique harvests the adult insects, but to get to the fatty larvae you must penetrate further into the mound.Intriguingly, a number of almost 2,000,000-year-old animal bones have been unearthed in South Africa. Their smooth rounded ends show clear parallel scratches. Scientists believe these are wear marks from repeated strikes and that the bones are actually Australopithecine tools, used for one specific job.Lesnik: This is a prototype, basically, of the types of tools they were using two-million years ago. A tool like this can get through, especially if you have a fragment that has kind of a pointier end that lets you penetrate it. We can pretty confidently say that these bone tools were used to dig into termite mounds.Narrator: Breaking open the mounds could have given Australopithecines access to the nutritious fat of the termite larvae, instant brain food.Lesnik: By just adjusting, a little bit, how they utilize the same resource, it’s probably enough to get them that extra fat in their diet that contributed to supporting this little bit larger brain.Narrator: Insects may well have provided our ancestors with key nutrients at a crucial point in their development.

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Was Eating Insects Key to Human Brain Evolution?

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Support Provided By

Explore More

The Case for Eating Bugs

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Insects Make Protein More Efficiently Than Mammals