Bigger nostrils: To better cool the air when breathing in hot weather.
Thinner facial features: The face can be narrower and longer to dissipate body heat faster.
Darker skin: Melanin levels increase to protect against sunlight.
Slanted, squinting eyes: Like a natural eye protection against intense sunlight.
More prominent brow bones: To prevent sweat from running into the eyes.
Hair may be sparser or absent: The scalp may be more bare to retain heat.
