On: The giraffe neck evolved for sexual combat?

[ramblerman]

Is there a limit to how much male and females can practically diverge in mammals?

I'm not at all schooled in genetics, so genuinely curious. But I could imagine that you can't have 2 genders of the same species that are completely different. Perhaps the neck length is such an attribute?

[pvaldes → ramblerman]

> I could imagine that you can't have 2 genders of the same species that are completely different.

This is called sexual dimorfism and is not a rare event. Really extreme examples appear in some deep sea fishes in the order Lophiiformes

I mammals is not so extreme, but it occurs also. Both genders having a different size is common and is what we would find in giraffes if the neck were developped just for fighting.

[redbread → pvaldes]

In some of those fishes the dimorphism is so extreme that the male is basically parasitic to the female. E.g. Ceratiidae