The only primate that's 100% carnivorous has eyes bigger than its brain

Tarsiers, tiny nocturnal primates native to Southeast Asian islands, eat nothing but live prey, insects, lizards, even small birds, making them the only primates that are entirely carnivorous. Each eyeball is roughly the size of the animal's brain and too large to rotate in its socket, so tarsiers instead swivel their heads almost 180 degrees in either direction.

— Genus first described by Étienne Geoffroy Saint-Hilaire, Tarsier — 1812