Elephants have two types of photoreceptor cells (cone cells) found in the retina compared to three found in the human eye.
Cone cells are responsible for color vision whereas rod cells control the ability to see in dim light. Even though humans are able to see more varied color (due to that brilliant third cone cell), elephants can see better in dim light.
In fact, elephants can see as well as a color-blind human and they can see quite clearly at night, under the light of a full moon.
Due to this, elephants are an arrhythmic species while humans are considered diurnal, meaning that we see better during the day because we spend most of the night sleeping.
But ... an elephant is not able to see in pitch black, if storm clouds cover the moon for example, but in Kenya, most nights are lit beautifully by a shining moon, perfect for a species that enjoys to frolic underneath it.