Study gets an earful of how mammals developed hearing

January 13, 2016
Study gets an earful of how mammals developed hearing
A study used marsupials, such as this rat kangaroo, to challenge current ideas about how mammals evolved stronger hearing than reptiles. Credit: Stephanie Hing

An international study led by University of Queensland researchers has challenged a long-held idea about how mammals evolved more sensitive hearing than reptiles.

UQ School of Biological Sciences researcher Dr Vera Weisbecker said the development of the mammalian middle ear represented an "extreme transformation" in the evolution of mammals from reptile-like ancestors, but existing scientific theories about how and why were based on insufficient data.

"One of the problems with earlier studies on is that scientists saw a relative shrinking in size of , as well as a movement away from the jaw joint, possibly under the influence of a rapidly expanding brain," she said.

"Because scientists look to such development processes to find out about evolution, these processes were interpreted to reflect the evolution over time of the mammalian middle ear.

"However, with a patchy fossil record, there weren't enough developmental data available to draw such conclusions.

"The evolution of the middle ear has been a hotly-debated area of developmental biology since 1837, but there is little to trace the details of this process.

"Over 320 million years of , three bones of the ancestral reptile-like jaw joint, initially devoted to feeding, shrank and 'retooled' to form bones entirely dedicated to a new purpose of conducting sound more sensitively towards the .

"It's not known why this change occurred, but it is thought that by extending their range of hearing to include high-pitched sounds, mammals could improve their detection of prey, such as small insects in the dark.

She said CT (computerised tomography) data from marsupials and monotremes revealed there was no support for some of the existing theories about mammalian development.

Dr Weisbecker said the study, published today in the Proceedings of the Royal Society B, highlighted a need for further fossil evidence to test widely-cited evolutionary theories.

Explore further: Paleontologists discover a new Mesozoic mammal

More information: Mammalian development does not recapitulate suspected key transformations in the evolutionary detachment of the mammalian middle ear. Proceedings of the Royal Society B. DOI: 10.1098/rspb.2015.2606

Related Stories

Paleontologists discover a new Mesozoic mammal

October 8, 2009

Pittsburgh, Pennsylvania, USA…An international team of paleontologists has discovered a new species of mammal that lived 123 million years ago in what is now the Liaoning Province in northeastern China. The newly discovered ...

Long-sought fossil mammal with transitional middle ear found

April 13, 2011

Paleontologists from the American Museum of Natural History and the Chinese Academy of Sciences announce the discovery of Liaoconodon hui, a complete fossil mammal from the Mesozoic found in China that includes the long-sought ...

Recommended for you

More reasons to eat your broccoli

June 22, 2016

Love it or hate it, broccoli is touted as a superfood, offering an array of health benefits. And it's about to get even more super.

Monkeys get more selective with age

June 23, 2016

As people get older, they become choosier about how they spend their time and with whom they spend it. Now, researchers reporting in the Cell Press journal Current Biology on June 23 find, based on a series of experimental ...

Team discovers new origins for farmed rice

June 22, 2016

Chew on this: rice farming is a far older practice than we knew. In fact, the oldest evidence of domesticated rice has just been found in China, and it's about 9,000 years old.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.