As the sun slowly set above the painted desert, in balance did the moon rise above the sun, signaling the change of shift between day and night. Below, the apes huddled together fearfully, knowing that with the coming of night came the dangers that accompanied the concealing darkness. They gathered near the mouth of a cave. One ape was missing, earlier taken by the local leopard, but the other apes did not register this fact. They had not yet learned to count.