#but it isn’t driven what mutations occur and when are fairly random

[snarltoothed]

i love that they applied the sex-based color patterning argument to mammals.

there’s a reason you see sex-based color patterning in birds and reptiles and not in mammals. birds and reptiles, on a historical evolutionary basis, have had better color vision than mammals. the evolutionary beginning of the mammalia order was largely comprised of burrowing rodent-like animals who, living in dark underground environments where color saturation is naturally low, had little need for a wide range of color perception.

we still see this reflected in many mammals today, it’s common knowledge that cats and dogs (and many other mammals) cannot percieve color in the same way that humans do. for a very long time there was no evolutionary benefit to any male mammals having bright colorations like some male birds/reptiles do, because mammals did not have high quality color vision.

there are actually exactly two species of mammals who have re-evolved both color vision and sexually dimorphic color-patterning: mandrills and baboons. this supports the theory that sexually dimorphic color-patterning only happens as a way to attract a mate in animals that can actually see those colors, if that theory needed support.

it’s worth noting many other primate species (including us) have re-evolved color vision but not sexually dimorphic color-patterning, because evolution is neither rational nor linear and not all species capable of evolving a certain trait will evolve that trait. there are also species of birds and reptiles who do not display sexually dimorphic color-patterning. this person’s whole argument is… just irrelevant.

now that i’m done being annoyed by the lack of research this person put into their shoddy evolutionary biology take FUN FACT ABOUT BREASTS:

as far as I have been able to find, there are only TWO species which develop fatty breasts during puberty and retain them while not pregnant/nursing: us and elephants! (although researching elephant breasts is not an easy task and i’m not 100% sure of the reliability of some of the sources i read — if anyone is an elephant expert and i’m wrong in any way please correct me!)

Ignoring the fact that this is absolutely not the limit of sexual dimorphism (colours and feather lengths? Did you read about peacocks and then just... stop?), humans are massively sexually dimorphic, far more than many animals! We are one of the few mammals that retain significant breasts when not nursing, the strength between the sexes and size to match is clear, voice pitch, and so much more.

The fact that it is a bimodal distribution does not make it any less sexual dimorphism!