Through the eyes of a wild animal: Part 2

Our general idea of an eye is a round white ball with a black circle in the middle of it. However not all animals have this kind of geometrical arrangement. One example you would be most familiar with is the cats eye, which takes an elongated oval shape during the day time. But you probably wouldn't have come across some of these unusual pupil shapes that I've got below.


Most of us know the cat's version of the story. These cute fur balls have eyes that are able to see in dark conditions, increasing their sensitivity to light. Thus to protect their eyes from the glare of the sunlight during daytime the pupils contract to a mere thin vertical line. And if you see a cat lying around with droopy eyelids with that typical 'don't care' attitude, it's nothing more than trying to protect his eyes!


Next time you visit New Zealand, you can directly look in the eye of a local and see if this is true. Sheep and even horses (below) have a horizontally elongated pupil, increasing their field of view to around 290 degrees. Again another adaptation for a animal of prey.


I have no idea why these beasts have got a bean shaped pupil, the elongation is probably to do with being the hunted party.


Look at those heavy eyelashes! Would work very well for a mascara advertisement!!?
Seriously, the square shape is a very uncommon shape in nature. The heavy lashes are to protect their eyes against sand storms, but square pupil?? no idea.


That shape looks quite funny, but that bump in the pupil is to give the hippo the ability to see out over the surface of the water. So he can keep himself half immersed in his luxurious bath and gaze out over the water level.


The magnificent horse has a blind spot directly in front of it, so even if he can see a wide field of view, the image will have a dark slit at the front.


This half circle can be rotated. So when the deer is grazing the hemispheric pupil will come down, keeping level with the horizon.

I must mention that I borrowed these pictures from this site (what with all these allegations of photo theft going around in the blogosphere!) And if you do like to know some more interesting stuff about how frogs, birds etc use their vision you will find them here.