This is a very smart gazelle (Thomson) all the females are giving birth the same day, if it's a dry periode they just wait until there is grass again, they can wait around 1-1,5 mounth before giving birth.
In Kruger there is around 600.000 thomsons, so from one day to another there is 1.2 mill.
The lions are very bussy that day.. But when there is 1.2 mill. the lions can't kill alle of them.