Dinosaurs could hear as well as birds - making them even better hunters than previously believed, according to new research

Dinosaurs could have sensed sound as sharply as birds, making them even better hunters than previously believed.

The process used by birds to hear has been detected in alligators, which are the closest living relative to the dinosaur, according to Daily Mail.  

It could means that T-rex and other carnivore dinosaurs identified the location of prey with their ears as much as their eyes.

An owls' sense of hearing is so sharp it can hear a mouse moving around under a covering of snow. 

Birds are exceptionally good at creating neural maps of the location of where sounds originated.   

These maps of where the sound came from uses a technique called the 'interaural time difference'.

 

In a study of alligators, scientists found that the reptiles build neural maps of sound in the same way birds do.

Animals process the tiny differences in time it takes a sound to reach each ear to work out where it has come from.

This is known as the interaural time difference and different animals process them in different ways. 

Little was previously known about how alligators do this, but new evidence suggests that reptiles form neural maps in the same way as birds.

This suggests the hearing strategy existed in their common ancestor - the dinosaurs, say scientists.

Smaller dinosaurs would also have benefited from sharp hearing by being better able to escape predators.  

Most research into how animals analyse interaural time difference has focused on physical features such as skull size and shape.

Lead author on the study Professor Catherine Carr from the University of Maryland believed it was important to look at evolutionary relationships to understand the process.

Professor Carr, of Maryland University in the United States, said: 'Our research strongly suggests this particular hearing strategy first evolved in their common ancestor.

'The other option - that they independently evolved the same complex strategy - seems very unlikely.'

Birds have very small head sizes compared with alligators but the two animals share a common ancestor - the archosaur.

It's a reptile that includes the dinosaurs and pterosaurs, but is only survived today by the crocodiles.

Archosaurs began to emerge around 246 million years ago and split into two lineages - one leading to alligators and the other dinosaurs.

Although most dinosaurs died out after an asteroid smashed into Earth 66 million years ago some survived to evolve into modern birds.

The latest findings indicate the hearing strategy birds and alligators share may have less to do with head size and more to do with common ancestry.

To study how alligators identify where sound comes from the researchers anaesthetised 40 alligators and fitted them with earphones.

They played tones for the sleepy reptiles and measured the response of a structure in their brain stems called the nucleus laminaris.

This structure is the seat of auditory signal processing. The results showed alligators create neural maps very similar to those previously measured in barn owls and chickens.

The same maps have not been recorded in the equivalent structure in mammal brains, which process sounds differently to birds and reptiles.

N.H.Kh

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