Date:

2-million-year-old fossils reveal hearing abilities of early humans

Research into human fossils dating back to approximately two million years ago reveals that the hearing pattern resembles chimpanzees, but with some slight differences in the direction of humans.

Rolf Quam, assistant professor of anthropology at Binghamton University, led an international research team in reconstructing an aspect of sensory perception in several fossil hominin individuals from the sites of Sterkfontein and Swartkrans in South Africa. The study relied on the use of CT scans and virtual computer reconstructions to study the internal anatomy of the ear. The results suggest that the early hominin species Australopithecus africanus and Paranthropus robustus, both of which lived around 2 million years ago, had hearing abilities similar to a chimpanzee, but with some slight differences in the direction of humans.

- Advertisement -
This is a lateral view of the Paranthropus robustus skull SK 46 from the site of Swartkrans, South Africa showing the 3-D virtual reconstruction of the ear and the hearing results for the early hominins. CREDIT : Rolf Quam
This is a lateral view of the Paranthropus robustus skull SK 46 from the site of Swartkrans, South Africa showing the 3-D virtual reconstruction of the ear and the hearing results for the early hominins. CREDIT : Rolf Quam

Humans are distinct from most other primates, including chimpanzees, in having better hearing across a wider range of frequencies, generally between 1.0-6.0 kHz. Within this same frequency range, which encompasses many of the sounds emitted during spoken language, 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 in living subjects,” said Quam. “So we were interested in finding out when this human-like hearing pattern first emerged during our evolutionary history.”

These are hearing results for the early hominins. Points higher on the curve indicate greater auditory sensitivity. Note the sharp dropoff in sensitivity above about 3 kHz. CREDIT : Rolf Quam
These are hearing results for the early hominins. Points higher on the curve indicate greater auditory sensitivity. Note the sharp dropoff in sensitivity above about 3 kHz.
CREDIT : Rolf Quam

Previously, Quam and colleagues studied the hearing abilities in several fossil hominin individuals from the site of the Sima de los Huesos (Pit of the Bones) in northern Spain. These fossils are about 430,000 years old and are considered to represent ancestors of the later Neandertals. The hearing abilities in the Sima hominins were nearly identical to living humans. In contrast, the much earlier South African specimens had a hearing pattern that was much more similar to a chimpanzee.

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 1.0-3.0 kHz. It turns out that this auditory pattern may have been particularly favorable 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.

- Advertisement -

“We know these species regularly occupied the savanna since their diet included up to 50 percent of resources found in open environments” said Quam. The researchers argue that this combination of auditory features may have favored short-range communication in open environments.

That sounds a lot like language. Does this mean these early hominins had language? “No,” said Quam. “We’re not arguing that. They certainly could communicate vocally. All primates do, but we’re not saying they had fully developed human language, which implies a symbolic content.”

The emergence of language is one of the most hotly debated questions in paleoanthropology, the branch of anthropology that studies human origins, since the capacity for spoken language is often held to be a defining human feature. There is a general consensus among anthropologists that the small brain size and ape-like cranial anatomy and vocal tract in these early hominins indicates they likely did not have the capacity for language.

“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.

Ignacio Martinez, a collaborator on the study, said, “We’re pretty confident about our results and our interpretation. In particular, it’s very gratifying when several independent lines of evidence converge on a consistent interpretation.”

How do these results compare with the discovery of a new hominin species, Homo naledi, announced just two weeks ago from a different site in South Africa?

“It would be really interesting to study the hearing pattern in this new species,” said Quam. “Stay tuned.”

The study was published on Sept. 25 in the journal Science Advances.

BINGHAMTON UNIVERSITY

- Advertisement -

Stay Updated: Follow us on iOS, Android, Google News, Facebook, Instagram, Twitter, Threads, TikTok, LinkedIn, and our newsletter

spot_img
Mark Milligan
Mark Milligan
Mark Milligan is a multi-award-winning journalist and the Managing Editor at HeritageDaily. His background is in archaeology and computer science, having written over 8,000 articles across several online publications. Mark is a member of the Association of British Science Writers (ABSW), the World Federation of Science Journalists, and in 2023 was the recipient of the British Citizen Award for Education, the BCA Medal of Honour, and the UK Prime Minister's Points of Light Award.
spot_img
spot_img

Mobile Application

spot_img

Related Articles

Roman-Era settlement unearthed in Alès

A recent excavation led by Inrap has uncovered a remarkably well-preserved Roman-era settlement on the slopes of the Hermitage hill overlooking Alès, southern France.

Excavations in Olympos reveal ancient mosaics and sacred inscriptions

Excavations in Olympos, Antalya province, have uncovered mosaic floors and inscriptions within a 5th-century church, part of a year-round project backed by Türkiye’s Ministry of Culture and Tourism.

Mammoth bones uncovered during road construction works

The Construction of the S17 Piaski–Hrebenne highway near the Arabunie village in Zamość County has revealed the remains of what is believed to be either a woolly mammoth or a forest elephant.

Hidden Medieval tower unearthed in Lublin reveals forgotten chapter of city’s past

Archaeologists have uncovered the remains of a previously undocumented medieval tower within the grounds of the former Pobernardine monastery complex, near the Church of the Conversion of Saint Paul on Bernardyńska Street.

Sinkhole reveals lost remains of medieval hospital

A sinkhole that formed outside the York Theatre Royal has led to the discovery of what could be one of England’s largest medieval hospitals.

Chalcolithic cultural treasures unearthed in Caucasus

Archaeologists from the Institute of Archaeology of the Russian Academy of Sciences have uncovered 13 Chalcolithic-era sites, each yielding a wealth of cultural artefacts and material evidence.

Study reveals East Asia’s earliest gold-inlaid spear sheath

In 1954, a bronze spear sheath dating from Japan’s Kofun period (AD 300–538) was found beneath a rock on Okinoshima, a sacred island located off the coast of Munakata, Fukuoka.

Cache of military helmets from both World Wars discovered during roadworks

Road construction works in the Polish city of Wroclaw have unearthed an unusual cache of military objects from WWI and WWII.