4
$\begingroup$

Among animals the ability to control ear muscles is pretty common, but only a few humans have the ability. Is it because we in general lost this ability ?

$\endgroup$
4
$\begingroup$

Yes, humans have lost the ability to move their ears toward sounds like many other animals such as cats and rabbits.

It is thought that our ancestors lost the ability to move their ears around 30 million years ago when

Ear size decreased and the associated musculature changed 1 (Steven Hackley).

A review from Steven Hackley outlines the evidence that the neural circuit remains in modern human brains. Apparently, the neural circuit still responds to directional sounds and may cause our ears to curl slightly (2 - 3 mm).

$\endgroup$
-1
$\begingroup$

This adaptation would have very little pressure on gene pool selection, as it provides little to no advantage other than slight, likely negligible, hearing improvement.

As survival fitness in terms of hunter-gatherer qualities, such as those of keen hearing and sight, are today meaningless in terms of reproductive viability, this phenotype would not persist over time, in my opinion.

$\endgroup$
  • 1
    $\begingroup$ Welcome to SE Biology. I think you've only alluded to an answer for the question, which I read as Do we have an ancestral group that lost the ability to control their ear muscles? Your answer concerns why we could have lost the ability to control our ear muscles. $\endgroup$ – Michael_A May 31 '18 at 8:42
  • $\begingroup$ Hi, thanks for having me. He's asking 'is it because we in general lost this ability'. I'm saying 'yes, we as a species have lost this ability due to lack of genetic selection for the trait, although it still likely shows up in some gene pools sporadically'. See definition of vestigial. $\endgroup$ – Hunter Frazier Jun 1 '18 at 0:01
  • $\begingroup$ No worries. Editing to include what you have summarised in your comment would improve the answer. $\endgroup$ – Michael_A Jun 1 '18 at 1:59

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.