why do goats have rectangular pupils

Goats have rectangular pupils primarily to provide them with a wider field of view and better detection of predators. Their horizontal, rectangular pupils allow them to see nearly 320-340 degrees around them without moving their heads, offering a panoramic vision essential for spotting threats in open grazing environments. Additionally, these pupils rotate to stay horizontal as their heads tilt, maintaining this wide field of view even when grazing. The rectangular shape also improves their visual depth perception in the vertical plane, which helps them navigate rocky, uneven terrain and jump with precision. Furthermore, the pupils adapt well to varying light conditions, especially at dawn and dusk, by allowing more light intake sideways while minimizing glare from above, which is important for their crepuscular activity. In summary, the rectangular pupils are an evolutionary adaptation that helps goats survive by enhancing their ability to watch for predators, navigate rough landscapes, and function effectively in low-light settings.