Color blind people have a tendency to better night vision and an ability to be able to distinguish hues that remain unseen to those who do not have the disorder. This effect has been put to use in wartime aerial reconnaissance and bombing missions, as color blind people appear to be more able to distinguish camouflaged sites than those without the disorder. In males, this may result in improved hunting skills in low light levels. The prevalence of color deficiencies ranges from 1% to 14% in different populations and may be moderately correlated with how much twilight there is in the region. The duration of twilight is short at the equator but progressively longer at higher latitudes.