#slothmonday nº4

What could sloths hear?

The smallest skeletal bones of mammals are found in the middle ear. These are: the malleus, incus and stapes. These bones have the function of amplifying the sound that reaches the eardrum and transmitting it to the brain.

In several species of fossils sloths these bones have been found preserved, and in the case of Lestodon and Glossotherium, they have been studied to evaluate the hearing capabilities.

These studies showed that the bones of the middle ear of these sloths were very large compared to other terrestrial mammals, with a total mass similar to that seen in the middle ear bones of the Asian elephant. This implies a loss in hearing acuity for high frequencies, but it is an advantage for the detection of low-frequency sounds.

One possible explanation is that these sloths could use low frequency sounds for long-range communications.