Why do human females menstruate

[P3nT4gR4m]

Came across this article which seems to have just the balance between science and butthurt 

Far from offering a nurturing embrace, the endometrium is a lethal testing-ground which only the toughest embryos survive. The longer the female can delay that placenta reaching her bloodstream, the longer she has to decide if she wants to dispose of this embryo without significant cost. The embryo, in contrast, wants to implant its placenta as quickly as possible, both to obtain access to its mother's rich blood, and to increase her stake in its survival. For this reason, the endometrium got thicker and tougher – and the fetal placenta got correspondingly more aggressive.

[Mesozoic Mister Nigel]

Fascinating! I read another article a few years ago of a somewhat similar gist. I've always thought it was quite unfortunate that it's possible to get pregnant (and stay pregnant) when we don't want to, unlike some other animals which can simply re-absorb their young.

[P3nT4gR4m]

I wasn't even aware that all mammals didn't do it much the same way

It suggests to me that it'd make for a tough little bastard of an organism, tho. Compared to the other method.

[Mesozoic Mister Nigel]

I wasn't even aware that all mammals didn't do it much the same way

It suggests to me that it'd make for a tough little bastard of an organism, tho. Compared to the other method.

And indeed it does.