Chimpanzees, 4 organutans, 4 gibbons and 4 rhesus were given a choice between a standard invisible size of banana (i.e., covered by an opaque plaque) and a variable visible size of banana. All groups showed an approximate 2% "bird-in-hand" constant error, preferring the visible, but groups differed in accuracy of food size selection (difference threshold SDs). Chimpanzees interchangeably used visible foods or differently colored plaques as cues to the larger of 2 rewards, used any 2 visible foods or signs of foods, as a cue to a 3rd (invisible) food size, and "rank ordered" 5 plaques by brightness, etc., for the sole reward of securing 5 hidden foods in order by size.