[CAT] "Here's why cats have such weird eyes"

[rfmcdonald]

Science Alert carried Julia Calderone's Business Insider article looking at the science behind the cat's eye.

Cats have some of the most unique eyes in the animal world: Instead of having circular pupils like humans, the black parts in the centres of their eyes are vertical - which can adapt quickly and can open and close like the aperture of a camera. Why are cat eyes so special? It all comes down to how they use their vision, new research says.

By analysing 214 different species of land animals, researchers at UC Berkeley found that the way animals spend their day determines the shape of their pupils. The team published their study on 7 August 2015 in the journal Science Advances.

Pupil shape and size determines how much light gets to the eyes - and is then translated by the brain into a picture of the world around us. When it's dark out our pupils expand to let in more light and enhance our vision, but when it's bright out, our pupils get smaller to prevent overstimulation. Cat eyes do the same thing, but with much more finesse than humans.

Previous research has suggested that the thin-slitted pupils of domesticated house cats and other predatory animals allow for a wider range of muscle movements and for more light to enter the eye.

Thin slits in cats - as opposed to circular pupils - allow for a huge change between the constricted and dilated states, and are capable of undergoing a 135-to-300-fold change in area. Human pupils, for comparison, can only change their pupil area 15-fold, according to a press release from UC Berkeley.