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To: RobRoy

"If not, what evidence gives them the conviction to state such opinions as athoritative fact rather than wild speculation?
"

Skull details can tell a lot about the size and shape of the eyeball. Further, the position of the eyeballs in the skull, along with the grooves mentioned in the article can indicate what the animal's field of vision was.

As for the predator aspect, take a look at a cat or dog, then a rabbit. The predator has eyes that face forward, as do those of the T. Rex. That allows good 3-dimensional vision. The rabbit, on the other hand, has its eyes on the sides of its head. Their field of vision is almost 360 degrees, but they have poor 3-dimensional vision.

The prey animal has evolved to detect motion in a wide angled view. The predator animal has evolved to focus on the prey animal and track its movements.

Given a rabbit skull and a cat skull, any first year student can immediately identify which is the predator and which the prey.


61 posted on 07/03/2006 1:37:56 PM PDT by MineralMan (non-evangelical atheist)
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To: MineralMan
And the raccoon I saw this morning? Mainly a scavenger.

But beside the point, they may know where the eye sat, but they don't know what was IN the eyeball itself.

Also, the animal was so huge that I am surprised it could even outrun an elephant. Then again, if it's primary food was the Brontosaurus, it would have been child's play to chase them down, assuming they could even get their neck off the ground.
89 posted on 07/03/2006 2:02:56 PM PDT by RobRoy (The Internet is about to do to Evolution what it did to Dan Rather. Information is power.)
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To: MineralMan; RobRoy

Just to add to MinearlMan - herbivorous dinosaurs like horned dinosaurs,hadrosaurs (duck-billed dinosaurs), sauropods (long-necks) and Ankylosaurs, all had eyes on the sides of their head, giving them wider field of vision the better to see that TRex sneaking up behind them.....examination of the eye sockets in the skulls of Allosaurus, the top Jurassic predator, for example, shows that it had limited stereoscopic vision...90 million years later in the Cretaceous, its relatives, the Carcharodontosaurines (Carcharodontosaurus, Giganotosaurus), had much better stereoscopic vision per the same examination....if it works, it will be selected for...


244 posted on 07/03/2006 7:12:28 PM PDT by Al Simmons (Hillary Clinton is Stalin in a Dress)
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To: MineralMan
Given a rabbit skull and a cat skull, any first year student can immediately identify which is the predator and which the prey.

A lot of the fraternity / sorority types couldn't. But in principle you are correct.

However, the original disputation was whether or not T-Rex was scavenger or active predator. I haven't yet heard anyone seriously suggest that on the whole T-Rex was primarily a prey species. Except possibly with respect to the Calvinosaur.

Cheers!

386 posted on 07/03/2006 10:48:54 PM PDT by grey_whiskers (The opinions are solely those of the author and are subject to change without notice.)
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