Eye Shapes Are Different For Predators And Prey

Eyes of different animals are---different! Look at goats. They have "horizontal-shaped pupils, while rattlesnakes and domestic cats have vertical slits". These things happen for a reason, according to natureworld.

While scientists have been worrying about this, some studies of 214 species was published on Friday to give us the answer. Eye shape does help to give some animals an edge to survive. Predators can hunt if they have vertical pupils and circular pupils, but horizontal pupils enable other species to spot predators from a distance.

Check cats and geckos, who have vertical-shaped pupils. They can identify potential prey through vertical slits of their pupils, and spot their targets from left to right, according to dailytimesgazette.

"The vertical-shaped eyes also maximize stereopsis, or binocular disparity, and blur, in which objects at different distances are out of focus. By using the difference between close focus, the animals can judge their distance from a target and pounce on it," according to William Sprague, a postdoctoral researcher.

Researchers used computer models based on sheep's eyes. Herbivores could capture more light in the left and right of eye if the model's pupils are horizontal, while less light will get filtered in from below and above the eye. Hence, they will be able to become aware of the predators coming from different directions, say scientists.

Vertical pupils also help an "ambush predator" to check out the distance to its prey by "sharpening depth perception and its focus on a target".

Martin Banks, a visual scientist from Berkeley and lead author on the paper, said, "People had been saying that the horizontal pupil helps expand the horizontal view of the ground; they just hadn't shown that. Our contribution was to build a model and show that that happened."

However, when goats, horses or other grazing animals lower their heads to eat grass, their eyes rotate up to 50 degrees, keeping the pupils parallel to the ground.

Large predators such as tigers and lions have circular pupils, as their eyes do not have to compensate as much for those visual cues, when these animals are taller.

The research, which was conducted by a team of scientists from the University of California, Berkeley, and Durham University in Britain, was published in the journal Science Advances.