Animal Vision

[N S]

I want to know how much animals are like us.

Like humans, do animals also have irises of various colours? Do their eyes accomodate and function the same way?

It all is always being taught about humans, but to what extent are animals like us in their vision and eyes?

[Moontanman]

I want to know how much animals are like us.

Like humans, do animals also have irises of various colours?

 

Some do, some don't, some don't even have irises, haven't you ever looked into the eyes of various animals? Cats have variously colored irises, as do dogs but insects have totally different eyes, compound eyes, but their eyes can be wildly varying in color as well..

 

Do their eyes accomodate and function the same way?

 

Yes, if not precisely the same the end result is the same... but if you mean mammals then yes, pretty much the same way..

 

It all is always being taught about humans, but to what extent are animals like us in their vision and eyes?

 

 

Some animals have eyes so good they make humans visually challenged others have eyes that see into the ultraviolet and others see into the infrared but yes many animals have vision very similar to humans...

[Ringer]

To add to Moontanman's post, you have to realize when you involve all animals you involve an incredibly diverse groups. Compound eyes, mechanical movement of lenses, huge variety of wavelength receptors, etc. It's difficult to compare so many different kinds of eyes in a simple thread.

[N S]

Ok thanks; I did not clarify that I was thinking about the eyes of animals more like us, say, all the vertebrates. Then beside the difference in the wavelenghts at which they operate, what distinguishing features can be observed in general in a wide group among them.

[dmaiski]

if you want to see the limits of vision see:

http://en.wikipedia.org/wiki/Mantis_shrimp

infrared, uv, 12 types of receptors, image processing handled by the eye itself, each eye is segmented for depth perception

 

on the other end of the scale: rats, cats, and bats

all of them would be considered legally blind by human standards

[Ringer]

on the other end of the scale: rats, cats, and bats

all of them would be considered legally blind by human standards

Some species of bats have good vision (http://www.sciencedaily.com/releases/2007/06/070615093131.htm) as do cats and rats. http://www.ratbehavior.org/RatVision.htm#Color http://en.wikipedia.org/wiki/Cat_senses#Sight

 

They may not have the same type of visual ability as us, but the same goes for us vs. them. It's comparing apples and oranges to say which is better.

[dmaiski]

true, but:

specific species of bats, cave dwelling fish and snakes, various lineages of rat...

 

dosent have quite the same poetic ring to it

[CharonY]

But that is an important point. There are large variation between species even within a genus. More distant animals, however, may have larger anatomic differences in their eyes, resulting in more fundamental differences in performance. I find it very strange to see cats in the list of bad eyes, however. I assumed that most would assume that cats have good eyes.

In ambient light their acuity is close to human's, whereas their reflective layer increases the performance by a lot at low light.

[dmaiski]

hmm i allways thought cats had pretty bad vision(20/100-20/200), it seems thats only true in bright light, in the dark cats have fairly good vision.

[Ringer]

Ok thanks; I did not clarify that I was thinking about the eyes of animals more like us, say, all the vertebrates. Then beside the difference in the wavelenghts at which they operate, what distinguishing features can be observed in general in a wide group among them.

That still doesn't narrow it down enough for anyone to give a good explanation that's not multiple text books.

[Moontanman]

yeah, vertebrates covers everything from hag fish to eagles...

[N S]

That still doesn't narrow it down enough for anyone to give a good explanation that's not multiple text books.

 

yeah, vertebrates covers everything from hag fish to eagles...

In that case, how about narrowing it down to terrestrial mammals?

[Ringer]

Well, depending on what you actually want to focus on (HA!), the very basic physiology is similar. Photoreceptors are excited by certain wavelengths, but those wavelengths vary depending on diet and environment of the animal. Shapes and ways to focus lenses also have pretty large variation.

 

Can you pose the question in a way that is more specific as to what you are interested in learning? There is just so much going on in any sensory organ it's difficult to compare even two types without being very specific as to what you're looking at.

[CharonY]

How about this as a starting point? http://en.wikipedia.org/wiki/Mammalian_eye