Final answer:
Primates with eyes facing forward possess stereoscopic vision, which might be an evolutionary adaptation for predation. This trait, combined with other features like grasping hands and nails, are indicative of primates' visual demands and larger brain size.
Step-by-step explanation:
The term for primates having eyes facing forward is stereoscopic vision. This anatomical feature allows for an overlap of visual fields, which provides primates with depth perception and three-dimensional vision. The evolutionary significance of forward-facing eyes in primates has been studied extensively. Notable anthropologist Matt Cartmill proposes that these and other traits such as grasping hands and feet, as well as the presence of nails instead of claws, may have been adaptations for predation rather than simply arboreal living. This idea is known as the visual predation hypothesis. Primates generally have larger eyes and brains, with a more prominent occipital lobe for processing visual information. The two main groups of primates are prosimians and anthropoids, with the latter having relatively larger brains and being mostly diurnal, relying more on vision than olfaction.