Thursday, May 8, 2014

What did the world look like to dinosaurs?

Seven-year-old Ben asked: "I was reading Dinotopia and I found the page where it showed the human vision and the dinosaur vision. Did dinosaurs really see that way?"

Hi, Ben,
Good question. Of course we’ll never really know how the world looked to dinosaurs, or for that matter, what things looks like to a dog or cat or bird. In fact, if you think about it, you can’t even be completely sure exactly how another person sees, and whether that’s different from the way you see, because you can’t climb inside their head.

But scientists are able to study the structures in the eyes of modern animals and they’ve found out some interesting things. 

Dogs, cats, deer, and other mammals do not have color receptors in their eyes that can sense the difference between green and red. So their view of the world may only distinguish light and dark, and maybe blue and yellow colors. Humans, apes, and monkeys have the addition of green / red color receptors, so we see those colors, too. 

Most birds seem to have as many color receptors as we do. But some birds, like hawks, may have sharper distance vision based on how their eyes are structured, and some other birds, like owls, surely see much better in the dark than we do. 

Mantis shrimp from Amasian Science

When it comes to color, some insects can see into the ultraviolet range, a kind of light that’s invisible to us. These unique abilities probably help bees and butterflies to see fruit or flowers. The mantis shrimp has 16 kinds of light receptors in its eyes, which apparently allow it to see images in polarized light and ultraviolet light that we can't see without special instruments.

Red faced Uakari Monkey from Flickr wbirt1
A good clue is that if animals have bright colors on them, then others of their kind can see those colors. That's why most animals aren't colored red, except for monkeys, which are unusual among mammals for having the same sort of color vision that humans have.

Inspector Myops from Dinotopia: The World Beneath

Returning to dinosaurs, if some dinosaurs were a lot like birds in other respects, they might well have had the added color sensing abilities of modern birds. Not only that, they might have been as colorful as birds.

So the illustration of "dinosaur vision" in Dinotopia may not be too far off.
Read more about color perception in animals at Amasian Science
or listen to the Radiolab episode on color.

Get a signed copy of Dinotopia for your inquisitive person in your life:
Dinotopia: A Land Apart from Time
Dinotopia: The World Beneath
or from Amazon: Dinotopia, A Land Apart from Time: 20th Anniversary Edition (Calla Editions)


Unknown said...

Good idea on dinosaurs possibly having vision like modern birds. I had never thought about that! I did some research on bird vision a few years ago and learned some fascinating facts- for example, some birds have 2 foveae (where the receptors are in a higher concentration than the rest of the retina) in each eye; pigeons are near sighted on the upper half of the retina and far sighted on the lower half (flying sight and pecking sight); and birds might be able to see into the ultraviolet range as well. It changed my outlook on the "bird brained" creatures, for sure!

Eugene Arenhaus said...

Most birds actually have four pigments, in some cases reaching into the ultraviolet, and some birds (e.g. Pigeons) even may have five. Since the common chordate ancestor apparently had five, three of which were lost by mammals (the third one in primates is a later mutation), it makes sense that the birds' ancestors, the dinosaurs, had vision pigments like those of birds.

Celia said...

The marvelous colors of plumage on some birds is a clue to their vision since they are meant to attract mates, hardly any point in it if they can't see them. Would make for a gorgeous world if they second illustration were accurate. Love those primary colors.

Jesse said...

James, if you haven't read The Oatmeal's piece about the mantis shrimp, it is most definitely worth it!

Emily Willoughby said...

Considering the iridescent sheen we now know probably existed in Microraptor and the bright red crest of Anchiornis, it seems like a reasonable conclusion that paravian dinosaurs had a similar visual range to modern birds!

Unknown said...

Recently I read that, because of their relationship with modern birds, dinosaurs not only had bird-like vision, but probably also (wait for it) taste like chicken.

AnkatsArt said...

Such a good question and such a wonderful answer!!! When I read it I immediatly wnated to anser as some of the other readers allready answered before, that birds can probably also see ultra violet.
Some bird species in which the sexes look the same (like some parrots or the blue tit) look different in ultr violet :)

K_tigress said...

Actually according to Daily Planet a TV show regarding the latest science news and discoveries, mentions that cats and maybe dogs may have some ability to see ultra violet vision.

I'm not surprised of that since I have noised there are some spots on my male cat, like his back and his really fluffy tail that seem to have a bit of sparkle to it.

It sort of reminds of this show about some of Australia's birds which featured budgies among one of those birds. They showed how a budgie might choose a mate based on how the spots on the male's face stand out showing how they see in ultra violet. Very interesting!

James Gurney said...

Thanks, everybody, for all these interesting comments. I'm learning, too. I will pass your added insights on to Ben.

dinodanthetrainman said...

Hello James

In a previous comment I asked

"are there any trains in Dinotopia? Shorly large dinosaurs could pull more than one wagon. I can see something like a steam tractor."

I am planning to order a copy of the new edition of first flight and was wondering if the original art could be of a truly Dinotopian train? Tho I would prefer it not to be strutter like?