Nature & Environment
Evolution: Ancient Human Fossils Reveal Our Hearing Patterns Resembled Chimpanzees'
Catherine Griffin
First Posted: Sep 28, 2015 01:19 PM EDT
Scientists have taken a closer look at some human fossils dating back at two million years ago, and have found that ancient hearing patterns resembled those of chimpanzee. The new findings reveal a bit more about what our ancient ancestors may have looked like and sensed.
In this latest study, the researchers wanted to reconstruct an aspect of sensory perception in several fossil hominin individuals from the sites of Sterkfontein and Swartkrans in South Africa. They used CT scans and virtual computer reconstructions in order to study the internal anatomy of the ear.
Humans are distinct from most other primates, including chimpanzees, by having better hearing across a wider range of frequencies between 1.0 to 6.0 kHz. Within this same frequency range, chimpanzees and most other primates lose sensitivity compared to humans.
"We know that the hearing patterns, or audiograms, in chimpanzees and humans are distinct because their hearing abilities have been measured in the laboratory of living subjects," said Rolf Quam, one of the researchers, in a news release. "So we were interested in finding out when this human-like hearing pattern first emerged during our evolutionary history."
In the South African fossils, the region of maximum hearing sensitivity was shifted towards slightly higher frequencies compared with chimpanzees, and the early hominins showed better hearing than either chimpanzees or humans from about 1.0 to 3.0 kHz. This auditory pattern may have been particularly useful for living on the savanna. In more open environments, sound waves don't travel as far as in the rainforest canopy, so short range communication is favored on the savanna.
"We feel our research line does have considerable potential to provide new insights into when the human hearing pattern emerged and, by extension, when we developed language," said Quam.
The findings are published in the journal Science Advances.
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First Posted: Sep 28, 2015 01:19 PM EDT
Scientists have taken a closer look at some human fossils dating back at two million years ago, and have found that ancient hearing patterns resembled those of chimpanzee. The new findings reveal a bit more about what our ancient ancestors may have looked like and sensed.
In this latest study, the researchers wanted to reconstruct an aspect of sensory perception in several fossil hominin individuals from the sites of Sterkfontein and Swartkrans in South Africa. They used CT scans and virtual computer reconstructions in order to study the internal anatomy of the ear.
Humans are distinct from most other primates, including chimpanzees, by having better hearing across a wider range of frequencies between 1.0 to 6.0 kHz. Within this same frequency range, chimpanzees and most other primates lose sensitivity compared to humans.
"We know that the hearing patterns, or audiograms, in chimpanzees and humans are distinct because their hearing abilities have been measured in the laboratory of living subjects," said Rolf Quam, one of the researchers, in a news release. "So we were interested in finding out when this human-like hearing pattern first emerged during our evolutionary history."
In the South African fossils, the region of maximum hearing sensitivity was shifted towards slightly higher frequencies compared with chimpanzees, and the early hominins showed better hearing than either chimpanzees or humans from about 1.0 to 3.0 kHz. This auditory pattern may have been particularly useful for living on the savanna. In more open environments, sound waves don't travel as far as in the rainforest canopy, so short range communication is favored on the savanna.
"We feel our research line does have considerable potential to provide new insights into when the human hearing pattern emerged and, by extension, when we developed language," said Quam.
The findings are published in the journal Science Advances.
Related Stories
Fossil Corals Shed Light on Earth's Ancient Climate
Cold Snap and Climate Change Killed Massive Crocodilians
For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone