Usually, in animals, female chooses her partner for mating. This is not like that in human. 🙂

Besides, if the female had been colourful and attracted attention, she could have easily got noticed by predators and killed. That would have affected the size of population or even species.
I think that trait was saved by natural selection.

The care for the appearance in the male is related to the choice made by the female. This is usually described as sexual selection. Males show off traits that are decraesing their fitness to convince females that they are strong and healthy (ie escape predators).

Poison is probably right in the male dominated human society, women are the one who needs to show off to be selected. Evolution of society toward less gender bias in many countries probably explain why we men now need to care about basic grooming 😉

Aw, it’s not?

Changes according to the person… 🙂
PS: But I can not resist the fact that I like to look good to myself too. I mean not only for someone. It can be an instinct, I don’t know. 😉

species where the male has low parental investment often have brightly colored males

species where the male has high parental investment (like humans) the difference between males and females is not so distinct

thats just a general rule of thumb

In the animal world, I always thought that females picked males by their desirable triats ( Like if they win a fight, they’d want the stronger one. Or the more colourful one.)

I groom myself, somewhat lol. What about all the pressures of having a six pack, hair on your head etc?