Stories tagged bite

Aug
10
2007

A shark, doing it's best: Mostly he just wants to be left alone.    (photo by Mshai on flickr.com)
A shark, doing it's best: Mostly he just wants to be left alone. (photo by Mshai on flickr.com)
Scientists in New South Wales and Florida are testing a new method of measuring the biting force of a great white shark using computer models.

Attempts have been made to measure sharks’ biting force underwater, in captivity and in the wild, although these are known to provide inadequate results. Sharks will generally do weak a “test bite” before applying the full force of their jaws, and these test bites are generally all that’s measured.

In this new experiment, researchers are dissecting a 2.4-meter long great white shark, in part to make an extremely accurate computer model of its anatomy, and in part to drive home the point that the animal should have just allowed them to measure its bite while it was alive. Advanced computing methods, originally developed for “calculating stresses in structures such as bridges,” will then be applied to the model, and should provide a much more accurate range of the shark’s biting force.

This process contrasts sharply with my own, I believe, much more elegant test of shark biting power. There are several simple steps involved in my method: Step 1 – gather a variety of small to medium sized objects. Step 2 - Rate the hardness of these objects, not on an objectively quantified scale, but relatively (for example: The kitten is harder than the pillow, but not as hard as the dictionary). Step 3 - Take these objects to your nearest shark. Get the shark to bite the objects (this can be difficult, but the right combination of chum and verbal abuse should do the trick). You will then have a simple and easy to understand scale of shark biting strength (for example: the shark could crush the pillow, the kitten, the dictionary, and the cookie jar, but not the lawn mower engine). If you still feel, at this point, that you need a measurement that uses more universally accepted units, you can then crush similar objects by yourself, far away from the shark, using free weights, or forty-pound bags of dog food. These can then be easily converted into newtons, or pounds per square inch, or whatever your physics teacher requires.

If the computer model method proves to give reasonably accurate results, I suppose it will then be up to individual researchers to choose that method or mine. It will just depend on whether someone doesn’t want to get their hands dirty, or if they care about style and integrity.

May
20
2007

I am often complimented on the condition and arrangement of my teeth. In particular, I have a very specialized space, or "gap," in between the central incisors of my upper jaw, something frequently admired by friends and strangers alike. This "gap" is a near-perfect adaptation the requirements of my diet - it makes short work of chocolate chip cookies, and I think "evisceration" is the most accurate term to describe its effect on burritos, and other soft food items. It is a source of great personal pride.

However, as they have in so many other ways, the long-dead Tyrannosaurids (the family of the T. Rex) have once again put me to shame.

Comparing CT scans of fossilized Tyrannosaur skulls with those of non-Tyrannosaur theropods (two-legged meat eaters), a group of Canadian scientists have recently shown that "fused, arch-like nasal bones are a unique feature of tyrannosaurids."
Tyrannosaur Nasal Bones: T-rex nasal bones and how they fit onto the skull. (Credit: Dr. Eric Snively, University of Alberta)
Tyrannosaur Nasal Bones: T-rex nasal bones and how they fit onto the skull. (Credit: Dr. Eric Snively, University of Alberta)

What's so special about "fused, arch-like nasal bones" you ask? Everything, says University of Alberta researcher Dr. Eric Snively. Previous estimates for the bite strength of Tyrannosaurids (long assumed to be one of history's top biters, second only to new-metal star Fred Durst) have been so high that the act of biting could have crushed the Tyrannosaur's own head. The fused nasal bones, however, would have allowed a Tyrannosaur to employ the massive strength of its head and neck with out harming itself. Larger theropods, such as the carcharadontosaurus and giganotosaurus, would have been unable to match the skull strength of even a medium sized tyrannosaur.

So where does this now place the T. Rex in the old hunter/scavenger debate? Dr. Snively and the coauthors of this research describe the T. Rex's jaws as a "zoological superweapon." But scavengers often display massive bone-crunching teeth and jaws (check out the archaeotherium and the hyenadont in the SMM's Dino's and Fossils gallery, if you get the chance - both have some impressive jaws, and both were probably at least occasional scavengers. While you're at it, take a look at our moveable T. Rex skull and jaws). Or does this research just plant the T. Rex more firmly in the category of "opportunist?"

Oh, also, here are a couple of fun bits of trivia from ScienceDaily's article:

"In a split second, a T. rex could toss its head at a 45 degree angle and throw a 50kg person five metres in the air. And that's with conservative estimates of the creature's muscle force."

"[Tyrrell museum researchers] showed that a T. rex's lower jaw could apply 200,000 newtons of force--that's like lifting a semi-trailer."

All pretty impressive, I guess, but, still, you should see me tear through a box of Twinkys. Grr.