Neural Maps of Interaural Time Difference in the American Alligator: A Stable Feature in Modern Archosaurs

Sound checking sleeping alligators

28 November 2019

Understanding how alligators locate sound could provide insights into how dinosaurs interpreted noise.

Many animals use the time difference between a sound reaching each ear to locate the sound’s source, much like map readers use triangulation points. Birds have been found to do this using neural maps in the brain’s nucleus laminaris, but not all animals are as easy to study.

A team that included researchers from the Technical University of Munich sedated 40 alligators and played them clicking noises through headphones. They monitored the unconscious beasts’ brain activity through electrodes attached over the nucleus laminaris and observed neuron-firing patterns most similar to those previously seen in chickens and barn owls.

Birds and crocodilians may have acquired a similar sound-processing part of the brain from their shared dinosaur ancestors despite evolving distinctly different head sizes and shapes.

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References

1. The Journal of Neuroscience 39, 3882–3896 (2019). doi: 10.1523/JNEUROSCI.2989-18.2019