Some 10,000 species of birds are currently recorded, some of them (some) have developed visual and auditory adaptations to track their prey at night. Did their distant ancestor, theropod dinosaurs, also adopt such changes? An extensive review of the inner ear and vision of several dozen living and fossil species identified a small dinosaur that could hunt at night.
Like an owl
The research was carried out by an international team led by Jonah Choynier of the University of Witwatersand in South Africa, which focuses on hearing the length of the bird’s cochlea (lagina), which allows the organ to process incoming sound information. is. . Comparisons between different fossils made it possible to note that some theropod dinosaurs such as the tyrannical dinosaurs and raptors had greater hearing capacity than the average, no doubt in locating their prey at greater distances. But this is the auditory organ, reconstructed in 3D, from the family’s small dinosaur Alvarezsauridae, theropods near the group of birds, which most interested researchers. Its cochlea is actually very long and awkward, being guided by the sounds emitted by its prey, similar to the barn owl, which is an owl capable of hunting in total darkness. Animals, baptism Shuvuia Desserts (“Desert Bird”), was discovered in the Mongolian desert and is about 70 million years old. It is a small family treat Alvarezsauridae, winged bipedes, and the latter was the size of a chicken. Their auditory organs suggest that they were capable of similar performance to owls and therefore ask for activity at night, the researchers said in an article published by the magazine Science.
Comparison of the barn owl cochlea (left) and the dinosaur. Credit: Jonah Choinier / Wits University.
A hypothesis was reinforced by testing the hypothesis of Shuvuiya. To catch him, sclerotic rings have proved invaluable. These small concentric bones surround the pupil and make it possible to reduce its size and thus calculate the amount of light that the eye can receive. They have no counterpart in mammals and therefore humans. This dinosaur has the largest proportions of all dinosaurs and birds, suggesting that it can be a very good night vision. For the study authors, these advanced nocturnal and auditory mink are adaptations for life in the desert. Temperatures that were too high in the day forced the animals to go out at night to carry out their various activities. Other physical features also request this explanation: Shuvuiya had very long muscular stretches with a long claw in his hand. An architecture that allowed him to dig for burger or dive inside small islands of bushes in search of prey. All these characteristics are found today in varying degrees, in animals living in the same type of environment. And so they had already been adopted by some dinosaurs millions of years ago!