Eye say.......

From one of my favorites, face book's "I fucking love science" - another geek post, because it was so visually intense. 

 How many can you guess?

Left to right, top to bottom: caiman, husky, gecko, crocodile, frog, python, squid, toucan, goat.

A passing thought; for all of these amazing colors of the eyes and the surrounding body parts, they have limited receptors in these visual systems for color perception compared to our own, and their depth perception, the height and width of their visual field / peripheral vision is different, and their perception of depth and movement is different, and some of the ranges of light and the ability to see in very low light is also very different from our own.

What you also don't see in these excellent photos is any indication of what these eyes look like in the dark, showing the reflection off of the tapetum lucidum, the reflective part of the eye that makes animals eyes in the dark stand out in bright contrast, or which gives  called eyeshine.  Eyeshine, that reflected light from the tapetum, varies by species, ranging from white, to blue, green, and red.  White occurs in fish; blue in herbivores; green in cats and dogs, and some wild carnivores; and red in rodents and birds.

That unfortunate red spot in the eyes on too many of our amateur photos of people is not from reflection of the tapetum; we lack that tissue (although other primates have it). We have red eye reflection because the light is reflecting off the fundus of the human eye, which is red. (That's what they dilate your pupils to examine in an eye exam.)