Tyrannosaurus rex's cheek grooves (below the eye sockets) and narrow snout cleared its sight lines, giving it impressive vision, according to a new study.
Posted on 07/03/2006 12:32:51 PM PDT by Al Simmons
In the 1993 movie Jurassic Park, one human character tells another that a Tyrannosaurus rex can't see them if they don't move, even though the beast is right in front of them. Now, a scientist reports that T. rex had some of the best vision in animal history. This sensory prowess strengthens arguments for T. rex's role as predator instead of scavenger.
Scientists had some evidence from measurements of T. rex skulls that the animal could see well. Recently, Kent A. Stevens of the University of Oregon in Eugene went further.
He used facial models of seven types of dinosaurs to reconstruct their binocular range, the area viewed simultaneously by both eyes. The wider an animal's binocular range, the better its depth perception and capacity to distinguish objectseven those that are motionless or camouflaged.
T. rex had a binocular range of 55, which is wider than that of modern hawks, Stevens reports in the summer Journal of Vertebrate Paleontology. Moreover, over the millennia, T. rex evolved features that improved its vision: Its snout grew lower and narrower, cheek grooves cleared its sight lines, and its eyeballs enlarged. ...
Stevens also considered visual acuity and limiting far pointthe greatest distance at which objects remain distinct. For these vision tests, he took the known optics of reptiles and birds, ranging from the poor-sighted crocodile to the exceptional eagle, and adjusted them to see how they would perform inside an eye as large as that of T. rex. "With the size of its eyeballs, it couldn't help but have excellent vision," Stevens says.
He found that T. rex might have had visual acuity as much as 13 times that of people. By comparison, an eagle's acuity is 3.6 times that of a person.
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T. rex might also have had a limiting far point of 6 kilometers, compared with the human far point of 1.6 km. These are best-case estimates, Stevens says, but even toward the cautious end of the scale, T. rex still displays better vision than what's needed for scavenging.
The vision argument takes the scavenger-versus-predator debate in a new direction. The debate had focused on whether T. rex's legs and teeth made it better suited for either lifestyle.
Stevens notes that visual ranges in hunting birds and snapping turtles typically are 20 wider than those in grain-eating birds and herbivorous turtles.
In modern animals, predators have better binocular vision than scavengers do, agrees Thomas R. Holtz Jr. of the University of Maryland at College Park. Binocular vision "almost certainly was a predatory adaptation," he says.
But a scavenging T. rex could have inherited its vision from predatory ancestors, says Jack Horner, curator of paleontology at the Museum of the Rockies in Bozeman, Mont. "It isn't a characteristic that was likely to hinder the scavenging abilities of T. rex and therefore wasn't selected out of the population," Horner says.
Stevens says the unconvincing scene in Jurassic Park inspired him to examine T. rex's vision because, with its "very sophisticated visual apparatus," the dinosaur couldn't possibly miss people so close by. Sight aside, says Stevens, "if you're sweating in fear 1 inch from the nostrils of the T. rex, it would figure out you were there anyway."
Stevens, K.A. 2006. Binocular vision in theropod dinosaurs. Journal of Vertebrate Paleontology 26(June):321-330.
"Flying Brick-Bat PING!!!"
So now there are people at the time of the dinosaurs? Hmmm.
Tyrannosaurus rex's cheek grooves (below the eye sockets) and narrow snout cleared its sight lines, giving it impressive vision, according to a new study.
Here's looking at you, kid....(see my last post)...
The T Rex birth rate is too low to support Evolutionary arguments of random mutations occuring fast enough to bring about species change.
Should I ping the list for this? It's not that much ...
If T-Rex was a vegetarian, as Hovind asserts, it was certaintly not a predator.
I guess I had assumed that the vision of the beast was related to they eyes within its actual eyes, of which we know nothing. I guess it is really only a factor of how far apart they are. Silly me.
Pardon me, but how is this important to mankind?
Forty years ago, scientists thought dinosaurs were slow, stupid, cold-blooded and lived in swamps. Now they think they were smart, fast, and had sophisticated hunting skills. Next they'll be telling us that dinosaurs had a vocabulary of over 1,000 words and could drive cars, if cars existed in the Jurassic period.
Where are the fossils with the high, wide snout without the cheek groves?
Do you expect more mutations/changes in low-birth-rate species or high birth rate species?
No. They are talking about a movie.
Ummm....you might try Googling "Gorgosaurus"....it did not have nearly as wide an eyeball ratio...
Doesn't mean there was anything worth reading in them even then back before they went downhill.
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