How many eyes does a butterfly have

A butterfly has two large compound eyes, one on each side of the head. Each compound eye contains thousands of tiny visual units (ommatidia), giving a very wide field of view and sensitivity to motion and color (including UV in many species). 

Popular figures cite up to ~17,000 ommatidia in some butterflies, though counts vary by species. Unlike simple human eyes, a compound eye forms a mosaic image, which is excellent for detecting movement and navigating while flying and feeding. 

For exams, write: “Butterfly = 2 compound eyes → many ommatidia (thousands) → panoramic vision; specialization supports foraging and predator avoidance.”