A study put forward on Friday by scientists from Binghamton University in New York concluded that human ancestors had ability to hear more like a person, and not like a chimpanzee. Scientists during their study examined two-million-year-old fossils and three tiny bones of middle ear.

The scientists already knew that modern humans can hear a wider range of frequencies — usually between 1 and 6 kilohertz (kHz) — than other primates can. This range includes sounds used in spoken language, which chimps and other primates can't hear as easily.

The results suggest that early humans had a greater sensitivity to some high-pitched frequencies than both modern humans and chimps do, the researchers said. This sensitivity is explained by the hominins' differences in anatomy, such as having a slightly shorter and wider external auditory canal (the tube that leads from the outer ear to the inner ear) and a smaller eardrum.

The study included two species from South Africa, named Australopithecus africanus and Paranthropus robustus. It was said that the species had better hearing ability than chimps or people in a range from about 1.0-3.0 kilohertz in a savanna habitat.

A paleoanthropologist named Rolf Quam of Binghamton University in New York said, the species if we compare to that of chimpanzees are more inclined towards higher frequencies and have maximum hearing sensitivity.

Lead researcher Rolf Quam, an assistant professor of biological anthropology at Binghamton University in New York said, "Previous studies have examined the differences between human and chimp ear anatomy and auditory abilities, but less is known about the hearing skills of early hominins."

Quam said sound range in rainforest does not travel that far, so short range communications are favorable for the savanna habitat.

"So the model works for chimpanzees — and, therefore, [for] any possible human ancestor, it should also provide reliable results," Quam added.

The human ancestor's ability started to get used to lifestyle changes. Homo sapiens, a species which had wider range of frequencies (1.0 to 6.0 kilohertz) and was found about 200,000 years ago is different from all the others.

Quam said that we are not discussing on the matter that the human ancestors had language or not, might be they communicate vocally.

"We know hearing patterns, or audiograms, in chimpanzees and humans are distinct because their hearing abilities have been measured in laboratory in living subjects, so we were interested in finding out when this human-like hearing pattern emerged during evolutionary history", said Quam.