Do Cats discriminate heights?
Yes, the visual cliff experiment shows that cats are excellent at discriminating heights.
Alot of cat owner are concerned about leaving their cats alone, especially residents of high rise buildings, since they fear that cats can't discriminate heights and may fall and suffer injuries. The concern has some truth associated with it but cats have a very good perception of height and they use their visual cues to the best of their safety.
The Visual Cliff experiment
A popular experiment of height perception is Visual Cliff. This experiment is used to investigate depth perception in different animals and humans. The apparatus in this experiment consists of a sheet of plexiglass and a cloth with high contrast checker board pattern. There are two height levels visible on the underside of the glass, a shallow area in which the checker board cloth is placed adjacent to the sheet of glass and a deep area in which the checker board cloth is placed 4 feet below the glass sheet.
Experiment on kittens, even at an early age of 4 weeks, showed excellent depth discrimination. Kittens preferred to sit on the shallow side of the cliff and when placed over the deep side they either froze or circled backward until they stepped on the shallow side.
Assassin in the house
The perception to height is innate in cats and is due to their hunting ancestry. They are excellent climbers with killer eyesight and prefer to ambush their prey. So your pet cat is an urban assassin, living in your home, who might have quit hunting but the skills are still their.
A counter argument to cats excellent height perception is the increasing stats of cat injuries resulting from High Rise Syndrome (the phenomenon of cats falling from higher than two stories). Although cats don't fall often but a distraction by its prey or falling asleep might cause a cat to take a plunge. Cats do try to grab the ledge by its claws when the falls seems evitable but building materials such as concrete and metal don't allow a successful grip.