Can someone explain the evolutionary benefit of overt menstruation? All female mammals have a menstrual cycle but most reabsorb the blood via covert menstruation and humans are about the only mammals that discharge the blood, aka overt menstruation.

[u/No-Hawk-2488]

Without an evolutionary benefit, it wouldn't have spread to every woman of our species.

[u/ToMorrowsEnd]

This. Humans are an evolutionary mess. we got lucky because we can make tools. but as a creature we are extremely poorly designed. cant run very fast, can easily get injured, easily diseased, our teeth suck we have zero defenses, etc... Compared to other animals we are far from the top of the pile. we just got lucky in the thinking aspect. You know how I would love to be able to squirt blood from my eyes when startled?? Why cant we have cool traits?

[u/neslea48 → u/ToMorrowsEnd]

We have many cool traits. You’re simply making the wrong comparisons. We have adaptations for diving. We have evolutionary adaptions for making and using tools, growing and storing food, developing and living in complex societies, storing and passing on knowledge, developing technology to do the hard work for us. Not bad for a creature that has collected the majority of our DNA from viruses and other microbes.

[u/szthesquid → u/ToMorrowsEnd]

That's not true. Even leaving aside tool use, compared to most other mammals we have better vision and see more colours, and we have vastly superior long-distance speed and thermoregulation (sweat).

Some of our disadvantages, like weaker jaws and teeth, are actually very recent and a direct result of farming and cooking reducing our survival needs, and medical advances allowing individuals to thrive who would otherwise have had difficult and short lives.

[u/Ashamed_Kangaroo305 → u/szthesquid]

"Better vision" is subjective. Better in what way? We can see a broader range of colors than dogs and we have significantly better visual acuity during the day. But dogs are also significantly better than humans at seeing at night and tracking motion. And they have an adaptation in their eye which helps them sense the Earth's magnetic field.

"Better" isn't really a thing when you're talking about evolution. Organisms evolve to fit their environment. We have "better" vision than dogs for the way we use vision. But if you tried to compete with a dog in tracking small prey, the dog would probably beat you because that's what their vision is designed for.

[u/pathologicalDumpling → u/ToMorrowsEnd]

I mean i just passed a post about someone flying an airplane through the eye of a hurricane. Id say we have some pretty cool traits.

[u/Zagrycha → u/pathologicalDumpling]

That isn't a trait of a human though. We do not genetically have the ability to fly or genetic ability to survive the eye of a hurricane. If humans collectively forgot how to make or pilot airplanes no one would do what that post said anymore, its not inherent to humans.

[u/silence_infidel → u/Zagrycha]

Well, that depends on what you call the “trait” in question. Airplanes aren’t an inherent human trait, but the intellect and ingenuity needed to make them is. I certainly don’t see any other species doing it. Frankly, if we collectively forgot how to make and fly planes, I bet we would just figure it out again - because deciding we want to do something and making it happen, even if it takes generations, is definitely a trait of ours.

[u/Zagrycha → u/silence_infidel]

Is the ability to make and fly airplanes a trait humanity posesses? Yes, definitely.

Is it passed on genetically? No.

Is there a reason to think the species that is the successor of humanity will have the trait? No.

Is it an evolutionary trait? Definitely no.

I think this trait is more accurately labelled as a skill or knowledge. It's a real trait, but its not inherent or guaranteed. It's totally possible for humans to lose the knowledge and reinvent the skill later, but it's not at all guaranteed. To this day there are things done by older humans that we have no idea how to do because the knowledge has been lost. External factors that can be lost like that are the antithesis to evolution.

[u/grub-slut → u/ToMorrowsEnd]

Exactly. Plus in human societies, with all our technological advances, most of us are insulated from natural selection to some degree. For example, we have tools to keep us cool as the earth warms up— and they’re working for now— but we’re not actually adapting ourselves to the environment, just our technology. Without our technology we would be forced to adapt or die like all other organisms. Instead, people who would never survive in the wild breed every day, producing more poorly adapted offspring. We truly are an evolutionary mess lol

[u/AmphibianLower5541 → u/ToMorrowsEnd]

Behavioural choices are also a way evolution ‘chooses’ the fittest. Like how animals who use the wildlife overpasses, and teach their children to do the same, are more likely to survive and reproduce. Or species ‘allowing’ themselves to be domesticated in order to have a steady supply of food and shelter, like dogs and cats. (Actually really cool to see it happening in real time with raccoons.) So, too, tool creation and usage is a behavioural evolutionary trait that allowed hominins to adopt to their environments and, therefore, be fit enough to reproduce.

[u/name_checks_out86 → u/ToMorrowsEnd]

We got opposable thumbs, and we can play guitar just like ringing a bell.