Scientists tested how early mammal predecessors could hear by studying Thrinaxodon, an ancient cynodont. They scanned a well-known fossil and made a 3D model of the skull and jaw. Then they used engineering simulations to see how parts would vibrate from sound.
The models show a thin membrane in a jaw crook could act like an eardrum and pick up airborne sound. This form of hearing seems to have evolved nearly 50 million years earlier than many scientists had thought. Sensitive hearing would have helped mostly nocturnal ancestors survive alongside dinosaurs.
Difficult words
- predecessor — an animal or species that came beforepredecessors
- cynodont — a group of ancient, mammal-like reptiles
- scan — to make a digital image of an objectscanned
- simulation — a test using a computer modelsimulations
- membrane — a thin layer of tissue or material
- eardrum — a thin part that vibrates with sound
- airborne — carried through the air by wind or sound
- nocturnal — active during the night, not the day
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How can good hearing help an animal that is active at night?
- Would you like to study fossils or 3D models? Why or why not?
- How do computer models and scans help scientists learn about the past?
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