Attacks on people by lions in Tanzania peak in the evenings of the days just after a full moon, and the reason is that those are the evenings that get dark early.

The study looked at five hundred attacks over thirty years. A full moon rises at sunset and lights the whole night; a moon a few days past full leaves a dark gap after sunset, which is when people are walking home. The Moon really is the variable — but the mechanism is human visibility, not lunar influence on lions.