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.
Then stop being a religious bully. It makes your religion, if you have one, look mean and petty.
The question is why would anyone want to share their beliefs with a$$holesfake Christians.
I've noticed you like to butt into conversations that have nothing to do with you. Do you not think its obvious by now that you, js1138 and OmahaFields are each other's bulletin board body guards? LOL!
Knock it Off!
posted on 07/04/2006 8:00:17 PM PDT by GOD (Please keep my commandments)
No, my assumption is correct unless OmahaFields corrects me. My conversation with him doesn't involve you.
You may assume whatever you like. What you assume has no impact on me.
Let me tell you something...perhaps you are directing direct questions to one poster in particular, but since you are posting on a public forum, your posts are fair game...whatever you say in a post, may be commented on by anyone else...
If you wanted an absolutely private conversation with someone, with no one else commenting, that is, what I thought Private freepmail is for...
I dont care what you think regarding me, or Omaha fields, or Js1138, or anyone else...if you think there is some sort of a conspiracy going on here, then you are welcome to your thoughts...
Anyone who reads your posts can comment on them...there is no butting in about it...public posts on an open public forum, are fair game...
And if they are not, one of the mods or Jim Robinson will tell me so...they run this place, and they run it with their rules...
My assumption about you is correct unless you correct me.
You really do need to chill out.
Okay, that's fine. Let's just say I don't care to coverse with you any longer so move along, please.
And I can comment on whatever you say, since its on the open public thread...
This happens to everyone all the time..I can be posting directly to someone, and someone else comes along, and gets into the conversation...so what...I take no offense at that, since I realize my posts are fair game for anyone...
If I had wanted an absolutely private discussion with someone, I would have taken it to Private Freepmail(and have often done that, when a poster and I get into a discussion, which is often off track of the main subject of the thread)...
So, if you post on the open public thread, whatever you post can be commented on by anyone else...
I assume that he is not a real Christian. A real Christian would be more concerned with his salvation and be at church rather than being a crude flake on a public board ...
It was a joke. Chill.
I wasn't even speaking to you. So, YOU knock it off!
I will move along, when I chose to...
Well, you sure ain't serving the Lord. That only leaves Satan.
I'm not concerned with what you think of me, quite the contrary. I just find it extremely amusing that you're hiding behind your biting words to avoid stating your own beliefs while mocking those that have them.
I doubt you know much about the Lord, or you would have claimed him by now.
If you don't want to converse anylonger, the polite, Christian thing to do is excuse yourself and leave. The rude, satanic way is to tell the other party to bug off.
It's always amusing to see a flame war over religion. Particularly on a science thread. If you really enjoy bullying people about their religion, there is an FR forum devoted to it.
This isn't it.
If you are married, ask your spouse if you aren't acting like an asshole tonight. If you aren't married. Im not surprised.
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