Artist’s rendering of an Australopithecus afarensis
When archaeologists hear whispers of humanity’s past, it’s through the painstaking work of piecing together a story from artifacts and fossilized remains: The actual calls, grunts, and other sounds made by our evolutionary ancestors didn’t fossilize. But working backward from clues in ancient skeletons, Dutch researcher Bart de Boer has built plastic models of an early hominin‘s vocal tract—and, by running air through the models, recreated the sounds our ancestors may have made millions of years ago.
Babies: As we reported yesterday, they just keep getting bigger. And while they haven’t always been trending towards obese, human babies have always been larger, relative to their mothers, than the infants of most other species. This make birth difficult and could have even changed the social structure of early hominids, steering human evolution.
Human babies are about 6.1 percent of their mother’s weight at birth, while chimp babies are about 3.3 percent. A new paper published in the Proceedings of the National Academy of Sciences takes a look at our extinct relatives to determine when this shift occurred, and suggests that it could even have encouraged our ancestors to come down from the trees and to form more complex social arrangements.
As anthropologist Jeremy DeSilva of Boston Univeristy pointed out in his new paper, “carrying a relatively large infant both pre- and postnatally has important ramifications for birthing strategies, social systems, energetics, and locomotion.” [Scientific American]