Humans regard food as essential; for all mortals who need to eat daily to sustain life, food is life itself. This was even more so for the Upright Apes who were still in the primitive tribal era, whose only source of food came from hunting.
Every Upright Ape subconsciously believed that the Lord of the Sky they sacrificed to would never respond to their acts of sacrifice, as it had always been so.
Therefore, the Upright Apes generously offered all the best food they had hunted that month as a sacrificial offering to the Lord of the Sky.
After all, this food, once the sacrifice was over, would remain untouched and be used for the upcoming grand sacrificial ceremony's feast, eventually ending up in their own stomachs.
But this time the sacrifice was completely different from before; truly, a presence very similar to the Lord of the Sky they worshiped had descended its will.