Is there a relation between the type of vision (monocular or binocular) and the food-habits of an animal?

Question

In herbivorous animals like cows, goats, sheep, rabbits etc, we mostly observe monocular vision i.e. the eyes of the animal are on different planes.

On the other hand, in most carnivores especially felines (cats), we see that the vision is wholly or partially binocular i.e. both the eyes are on the same plane.

Is there a direct relation between the type of vision and the food-habits of an animal?

If not, what other factors decide the type of vision (monocular or binocular) in an animal?

Answer 1

Best Answer - Chosen by Asker

Interesting! You've already gotten some good answers, but I'll add my two cents.
I think that, more than being related specifically to food-habits, this trait is related to habitat and overall habitus (which includes not only food type but also food consecution mechanisms, locomotor type and other characteristics of habitat use). And of course, to evolutionary history. All lineages have adaptations and constraints of their own.
As a basic consideration, most animals that live in terrestrial habitats move in a mostly 2-dimensional world. Flying and climbing animals are the exception, as well as those that may expect predators to come from above. Aquatic environments, on the other hand, are always very much 3-dimensional.

If we consider vertebrates (which I guess it's what your question was aiming at), most have eyes placed more or less laterally on the head, ensuring an extensive vision field with some (small) binocular central area. Of course, the tradeoff for lateralised eyes is that reduced superimposition of both eyes' fields, thus lesser binocular vision. In the same manner, frontal eyes reduce the total field of vision.
A (very partial) list of terrestrial vertebrates with frontal eyes and/or enhanced stereopsis (binocular vision):

-Plethodontid salamanders.
-Chameleons, geckoes, varanids (Komodo dragons), and many arboreal snakes, among reptiles.
- Strigiformes (owls) and Falconiformes (eagles, hawks...), but also the kakapo, a nocturnal Australian parrot, and the frogmouths (Caprimulgiformes Podargidae).
-Many generalized marsupials such as opossums; primates and felids.

Not all these animals are predators, and there are several predators with lateral eyes and mostly monocular vision.
So, in my opinion, the main factor is not so much what you eat, but how you get it and where you usually move.

For example, let's take the case of mammals. The earliest known fossils seem to have had nocturnal habits and partially frontal eyes, such as those seen today in opossums. From there, I can visualize different evolutionary paths tending to more laterally placed eyes in animals that have to avoid predators (such as many herbivores - e.g. hoofed mammals- , insectivores or omnivores), and more frontally placed eyes in mammals that require good 3-D vision, be it hunters (as felids) or species that move in a 3-D environment (primates), and/or have nocturnal activity.

Other vertebrate groups have different evolutionary paths and adaptive histories. For instance, the eyes of all birds are extremely large in comparison with other vertebrates, with very wide vision fields; and all birds have binocular vision to some extent. Only specialized predator birds have frontal eyes, but I guess that all birds use their enlarged cerebellum to calculate distances on the basis of the 20-30º binocular field.

Aquatic fish-like vertebrates privilege wider vision angles, but there are fish with good binocular vision, such as the hammerhead sharks and also many deep-sea bony fish species. In the case of the first ones, it could be a predator specialization, whereas in the latter case it could be related to vision in low-light environments.

Arthropods have a different system altogether, and I think their adaptations and constraints merit a separate discussion (what an elegant way of avoiding it!).

So, although we like to identify patterns that allow us better understanding of the biological world, I don't think there is a direct relationship with a single factor. The list of possible factors influencing vision type includes:
- phylogenetic history (including previous adaptations and constraints)
- locomotor habit (running, flying, climbing)
- feeding habit (including type of food and ways of searching for it)
- diurnal/nocturnal activity

I'm sure I'm leaving important things out... I'm not even sure if this all makes sense!

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Update: Gianguru, you're amazing. You're also reported.

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Asker's Comment:

Choosing Cali's answer as best was a no-brainer and Gian Guru, "doosron ke answer chori karna chhod tho!"

Answer 2

Yours is a great question. I've always wondered this.

Intuitively, it would seem that since most herbivores (plant eaters) have eyes on the sides of their heads this must facilitate their ability to notice predators more quickly.

Meat eaters (Carnivores)/Predators have binocular vision that gives them the opportunity to see depth...which must help them judge how far a prey is away and what behaviors to take to catch their prey.

I guess the "monkey" wrench in this whole predator (binocular) and prey(monocular) gets thrown out of whack when you think of fish.

Anyway...my two cents.

Answer 3

It's not a direct relationship, but there is definitely a corellation between diet and vision type.

Not all predators have binocular vision. Some predators are small enough that they can easily become prey to other predators, and so have to balance the hunting bonus that comes with binocular vision with the perception bonus that comes with the peripheral vision of more side-mounted eyes. Grasshopper mice, shrews and some of the small marsupial predators (like the Monito del Monte - my favourite mammal name) are good examples of predators that don't have binocular vision.

There are also critters that are not predatory, but have binocular vision. Many of these are arboreal or flying creatures (i.e. most birds) that would rather have the ability to judge distances between trees, and so sacrifice some of their detection abilities in favour of rapid and safe getaways. Monkeys are the most obvious example of this kind of vision.

Answer 4

some good responses already entered, but since you asked for possible other avanues of determination of the importance of sight to dinner habits, I'd suggest looking at brain percentage devoted to sight.

also teeth are a far more consistant hint at what an animal eats...

Answer 5

Interesting! You've already gotten some good answers, but I am sure this will help u a lot. More than being related specifically to food-habits, this trait is related to habitat and overall habits (which includes not only food type but also food consecution mechanisms, locomotors type and other characteristics of habitat use). In addition, of course, to evolutionary history. All lineages have adaptations and constraints of their own.
As a basic consideration, most animals that live in terrestrial habitats move in a mostly 2-dimensional world. Flying and climbing animals are the exception, as well as those that may expect predators to come from above. Aquatic environments, on the other hand, are always very much 3-dimensional.

If we consider vertebrates, most have eyes placed more or less laterally on the head, ensuring an extensive vision field with some binocular central area. Of course, the tradeoff for lateralized eyes is that reduced superimposition of both eyes' fields, thus lesser binocular vision. In the same manner, frontal eyes reduce the total field of vision.
A list of terrestrial vertebrates with frontal eyes and enhanced stereopsis (binocular vision):

-Plethodontid salamanders.
-Chameleons, geckoes, varanids and many arboreal snakes, among reptiles.
- Strigiformes (owls) and Falconiformes but also the kakapo, a nocturnal Australian parrot, and the frogmouths (Caprimulgiformes Podargidae).
-Many generalized marsupials such as opossums; primates and felids.

Not all these animals are predators, and there are several predators with lateral eyes and mostly monocular vision.
So, in my opinion, the main factor is not so much what you eat, but how you get it and where you usually move.

For example, let's take the case of mammals. The earliest known fossils seem to have had nocturnal habits and partially frontal eyes, such as those seen today in opossums. From there, I can visualize different evolutionary paths tending to more laterally placed eyes in animals that have to avoid predators (such as many herbivores - e.g. hoofed mammals- , insectivores or omnivores), and more frontally placed eyes in mammals that require good 3-D vision, be it hunters (as felids) or species that move in a 3-D environment (primates), and/or have nocturnal activity.

Other vertebrate groups have different evolutionary paths and adaptive histories. For instance, the eyes of all birds are extremely large in comparison with other vertebrates, with very wide vision fields; and all birds have binocular vision to some extent. Only specialized predator birds have frontal eyes, but I guess that all birds use their enlarged cerebellum to calculate distances on the basis of the 20-30º binocular field.

Aquatic fish-like vertebrates privilege wider vision angles, but there are fish with good binocular vision, such as the hammerhead sharks and also many deep-sea bony fish species. In the case of the first ones, it could be a predator specialization, whereas in the latter case it could be related to vision in low-light environments.

Arthropods have a different system altogether, and I think their adaptations and constraints merit a separate discussion
So, although we like to identify patterns that allow us better understanding of the biological world, I don't think there is a direct relationship with a single factor. The list of possible factors influencing vision type includes:
- phylogenetic history (including previous adaptations and constraints)
- locomotor habit (running, flying, climbing)
- feeding habit (including type of food and ways of searching for it)
- diurnal/nocturnal activity

this is just taken from pradeep

Answer 6

monucular

Source(s):

binocular