As humans we are much better at noticing small differences between humans than animals.
We are just more used to it.
Practical example, if you go to a farm, every cow looks almost the same to you, still the farmer can identify each on in mere seconds.
Same reason, he sees them every day and notices every small difference, you don't.
Phrazez t1_jaa4kc2 wrote
Reply to Eli5 why humans don’t resemble each other as much as other animals do? by That_one_guy_zion
They look identical to us.
As humans we are much better at noticing small differences between humans than animals.
We are just more used to it.
Practical example, if you go to a farm, every cow looks almost the same to you, still the farmer can identify each on in mere seconds. Same reason, he sees them every day and notices every small difference, you don't.