**Kim** @kimdanes · May 23, 2018, 17:25

**Kim** @kimdanes · May 23, 2018, 17:25

Kim @kimdanes

May 23, 2018, 17:25

Human body stuff, also probably me being moderately stupid? Show more

I have so many questions about evolution

Why do males have nipples but not be able to lactate? Like what possible reason could there be for making sure only half the population can feed infants?

Also, why nose hairs? What are they for, filtering air? Then why don't mouths have them?

Why do we have soft, easily hurt feet if we're supposed to walk barefoot everywhere

**Dngrsone** @Dngrsone@layer8.space · May 23, 2018, 17:47

**Dngrsone** @Dngrsone@layer8.space · May 23, 2018, 17:47

May 23, 2018, 17:47

Dngrsone @Dngrsone@layer8.space

Human body stuff... Show more

@kimdanes

Human males can lactate under certain circumstances.

The body starts developing using a standard template, the hormone mix during gestation (largely driven by the X and Y gene combinations) determines the construction/modification of certain features such as the sex organs and breasts.

Noses are for breathing, mouths for eating. Breathing through the mouth is a secondary thing.

Those of us who do walk barefoot develop calluses... tough skin on our feet.

**Kim** @kimdanes · 2018-05-23T21:51:50Z

Kim @kimdanes

Human body stuff... Show more

@Dngrsone for the ability to lactate I meant more big-picture, as in why did mammals specialize to have only half the population capable of lactation, since it sounds like an evolutionary advantage? But the rest of the info answered my other questions, thanks

May 23, 2018, 21:51 · Tusky · 0 · 0

**Dngrsone** @Dngrsone@layer8.space · May 27, 2018, 21:22

**Dngrsone** @Dngrsone@layer8.space · May 27, 2018, 21:22

May 27, 2018, 21:22

Dngrsone @Dngrsone@layer8.space

Human body stuff... Show more

@kimdanes You know, that's a good question. A quick search of the intarwebs yielded me one site (https://www.sciencedirect.com/science/article/pii/0022519379903345) with a sort-of answer that basically says because lactation is wired into being female, it just hasn't happened much, though the same searched yielded that several mammal species have done so, it looks like there only one kind of bat that does it normally. (search: https://www.google.com/search?q=male+mammals+lactate)