The eyes of deer and people share a number of features, but they also have a few significant differences. Unlike human pupils, which are round and when dilated do not span much of the eye ...

Deer are active around sunrise and sunset, making them neither nocturnal nor diurnal, but rather crepuscular. Their eyes have evolved to function in dim lighting, with pupils dilated to create a ...

Vertical pupils can be found in dogs, cats, vipers, geckos, crocodiles and some birds. Goats, sheep, deer, horses, frogs and toads have horizontal pupils. One advantage to slit-like pupils is ...

Many herbivores, like horses and deer, have horizontal, rectangular pupils, rather than vertical slits. The authors don’t think these pupils help with depth perception. But rectangular pupils ...