Sound loudness is measured in decibels. The volume numbers on your TV or speakers are arbitrary. People talk at about 60-65 decibels normally, while a train or a jackhammer are almost 100 decibels.
Do you know that there is an insect called the lesser water boatman (it lives in the water) which can make 92 decibels of sound by vibrating its penis?
As Zoe has explained, volume or loudness is measured in decibels. What we’re perceiving as sound are actually vibrations.
Humans are able to pick up these vibrations through our three tiniest bones (found in our middle ears), and called “auditory ossicles.” You may have heard their common names, which describe in Latin what they look like: malleus (hammer), incus (anvil), and stapes (stirrup).
Very early in mammalian evolution, these tiny bones weren’t all in our middle ear like they are today, they were actually part of our jaws! This shift, though, enabled us to have better hearing than our reptile relatives.
These ossicles are very rare to find in human evolution because they are so small, but increasingly detailed excavation methods might help change that!