It is known that black absorbs heat and white reflects it so why do indiginous
peoples of equatorial countries have very dark skins. conversely, other populations have lighter and lighter skins the further they are from the equator.
Skin cancer is extremely rare among dark-skinned people, simply because nature has provided their skin with the ability to produce extra melanin to protect them from harmful UV radiation.
it is obvious that heat absorption isnt the deciding factor
(although they tend to get taller and leaner towards the equator and this minimizes heat absorption (cross area thingey) and so heat absorption DOES matter in habitus)
it is to do with melanin and protection from photo-damage.
The black colour is derived from melanin in the skin, which acts as protection against UV radiation, which causes all sorts of damage to some pretty important systems within the body.