Chicken Nugget

Pierre: Wow, what’s that doing out there?

gray tabby cat looks out window

Pierre: Ashton, you might want to see this outside the window.

gray tabby cat looks away from window

Ashton: * YAWN * See what?

one-eyed brown tabby cat lounges on sofa back

Pierre: It’s a chicken nugget.

Ashton: A WHAT?

baby sandhill crane

Mother Sandhill Crane: I heard you, cat! Junior, it’s time to go.

sandhill crane

Junior: I’m going. I’m going.

baby sandhill crane

Pierre: See you later, chicken nugget!

gray tabby cat licks his lips while looking out window

Junior: I don’t think so, kitty.

baby sandhill crane

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Pierre: The head peep was sick this week, which is why you haven’t heard as much from us as you normally would. Caring for her is a full time job for us, especially when Nurse Newton falls down on the job. But never fear, Pierre, Physician Assistant, is right there to make sure she gets better.

In case you ever need to take care of your human, too, I thought I would share the most important thing to do: watch your human closely. Every time your human opens her eyes, she should see your face. That always makes humans feel better.

This means you need to follow your human from room to room. I knew the head peep was really sick when she lay on the sofa and watched television. She hardly ever does that. But I was right there to keep a VERY close eye on her.

Taking care of your human is exhausting work. Lucky for me, the head peep was in bed a lot where we could both be comfortable while I watched her.

Thankfully, she is on the mend now. It never would have happened if I hadn’t taken such good care of her. All of that watching was hard work, but it paid off! I’ll be napping extra the rest of the week to make up for the hours I missed while doing my medical duties.dex: 8675309; display: none; cursor: pointer;”>Save

Cats and Depth Perception

It’s common knowledge that it takes two eyes to see 3-dimensional images. So have you ever wondered how a one-eyed cat like Ashton gets around without bumping into things?

one-eyed brown tabby cat in loaf position

I know it was a concern I had when I realized she was going to lose her eye. But it’s surprising how well she compensates!

Let’s start with how most cats see.

Binocular Vision

The concept of binocular vision brings to mind a cat using a pair of field glasses. But the term binocular actually just means to see through two eyes, the way a normal cat does.

cat looking through binoculars. image credit: depositphotos/RasulovS

Each of your cat’s eyes sees a slightly different image because they are next to each other, and the image projected on the retina of each eye is slightly offset. Your cat’s brain puts the two slightly different images together into a single three-dimensional image.

cat wearing 3D glasses. photo credit: depositphotos/RasulovS

Perceiving the three-dimensional image is called stereopsis. This three-dimensional sight helps your cat catch fast-moving prey, since they can more accurately judge distances when it’s time to pounce.

The side-to-side displacement of your cat’s eyes is easier to gauge using vertical lines and contours, which is why cats, as predators, have pupils with vertical slits.

Vertical pupils that can open wide when hunting also help maximize the contrast between the sharpness of the object your cat is focusing on and the blur of the out-of-focus objects in the foreground and background. Those also help your cat measure distance so that every pounce, whether it’s on a mouse or on a wand toy, is accurate.

orange cat face. photo credit: depositphotos/c-foto

Monocular Vision

Seeing with only one eye, the way Ashton does, is called monocular vision. Hearing “monocular vision” may bring to mind a cat wearing a monocle, but both monocular and monocle use the same word prefix, “mono” meaning singular.

cat with monocle. Photo credit: deposipthotos/kuban_girl

When a cat can only see out of one eye, three-dimensional sight isn’t available to help judge how far away objects are, but there are plenty of other cues a cat can use instead:

Focusing – Whether focusing on an object makes the eye work to focus near or far.
Detail in objects – The texture detail of an object is more visible as an object is closer. Father objects show less detail and are more indistinct.
Relative size – An object looks larger when it is nearer. Objects moving toward the cat look like they are growing larger.

mouse cat toys, near and far.

Light and shadow – Both light and shadow help judge the height and position of an object.
Brightness – Closer objects appear relatively brighter than further objects.
Motion – Nearby objects seem to move faster than farther objects when moving at the same speed. This is called as the parallax effect.
Linear Perspective – Parallel straight lines appear to meet in the distance. The further separated the two parallel lines are, the closer the object is.

All of these are cues that a cat with two eyes uses to help judge distances to objects, too. In a sense, a cat using monocular vision only loses one of the many tools to help navigate the world.

one-eyed brown tabby cat dangles one paw