The grasslands were eerily quiet during the night, most of the monsters that could be seen running around and fighting during the day were absent from it, each one of them was sleeping, they weren't fully asleep however, the grasslands were still dangerous during the night and those beasts needed to be alert, otherwise they might end up as a meal.
Monsters that usually stayed underground during the day made their way to the surface as they carefully observed their surroundings, some lived deep underground and only came out every couple of days while others created nests in the ground from which they came out every single night.
The night in the grasslands was always a restless one, most of the monsters would target the young and the old beasts as they were easy prey while other, stronger monsters would go for the strong and healthy ones as they would provide more nourishment.