Why aren't humans nocturnal ?

[Apparition from Beyond the Veil]

Why aren't humans nocturnal ?

[Apparition from Beyond the Veil]

My guess is that it's because we rely on our vision more than smell or hearing (like many animals do). We came to excel as diurnal persistence hunters on the African Savannah during the heat of the day. Our upright posture and relative hairlessness facilitates the evaporative cooling of the body, hence humans perspire prolifically. We had the advantage over animals whose strategy was to remain still and/or in shade under the noonday sun.