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.
Yes, you can butt in anytime you want, but keep in mind you can easily offend others when they are not speaking to you. It's all in the approach...
I can only assume that they are not real Christians.
I already said what I think about this. When a poster makes Christians look like bullies, they must be swinging for the other team.
I find it odd that you're so quick to call others names and attack their religion, but hide behind those attacks to avoid mentioning your own beliefs. Like demkicker, I find it very strange.
Is that anyway to speak to God?
I have no idea what your religion is. I have, thought, ruled out Christianity.
Thanks for proving to everyone on the forum that you're a whacko. LOL!
I missed that post. These guys are so bad they probably are x'ed out of their church.
Yes you are correct, that approach is important...but approach on any thread, for any reason, whether someone is talking to you directly or not. is important...
Frankly I see nothing offensive in what I said, I merely pointed out that any post is fair game...and oh yes, I questioned why someone keeps posing the same question to someone who has already said, that they are not going to answer...
Seems to me, a refusal to answer should just be accepted...
God works in mysterious ways. You can never tell when God is testing you. You must have faith and not mock Me.
Earth to you: This isn't a flame war. You seem to think its fine to attack me and my religion. I'm not the bully here.
You are the one who is an asshole and I've noticed it on numerous threads. And you can quit with the lecturing. It really is pathetic on your part.
It would seem to be the Christian thing to do, particularly when it comes to a persons faith.
I haven't attacked your religion. Just you.
Now I get it. You only believe in your pathetic self.
Confirmed. No Christian would talk like that.
Glad you're admitting it, thanks.
I think you are coming around to the reality of whom you are talking to. If you mend your crude ways, I may allow you into Heaven after all.
People who can't even utter their own beliefs don't have a clue about other's religions.
'Time to watch fireworks', placemarker...
You really do need some professional help.
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