This video explores the diverse shapes and sizes of animal pupils, explaining the evolutionary reasons behind their variations. Anton Petrov examines scientific studies to debunk misconceptions and present a more accurate understanding of how pupil shape relates to an animal's lifestyle and survival strategies.
Vertical slit pupils: Primarily found in ambush predators, especially shorter ones. The vertical orientation provides a stigmatic depth of field, enhancing distance judgment for chasing prey, even without head movement. Height is a factor; larger predators like lions and tigers often have round pupils instead.
Horizontal pupils: Common in grazing animals. They act as built-in visors, maximizing light intake from the front and back while minimizing distracting light from above and below. These animals also exhibit cycliorotation, rotating their eyes to maintain a horizontal pupil orientation even when their heads are lowered.
Circular pupils: Found in a wide variety of animals with diverse lifestyles, indicating versatility. While less specialized than slit pupils, they offer a good balance of light gathering and field of view, suitable for active foraging and pursuit hunting. Taller animals, both predator and prey, tend to have circular pupils.
Bizarre shapes (W, U, multiple pinholes): These unusual shapes represent specialized adaptations. W-shaped pupils (cuttlefish) improve image contrast in aquatic environments. Multi-pinhole pupils (geckos) increase depth of field, crucial for nocturnal hunting. U-shaped pupils (rays and skates) reduce lenticular spherical aberration, improving focus and aiding camouflage.
