Dinosaur vacuums
March 25, 2011
Paleontologists have long been at odds over the reasons for sauropod's elongated necks. One camp argues that the giant vegetarians would stand in water and use them like snorkels, while the other believes they fed in much the same way as giraffes, using their height to pick leaves from tall trees.
A third and more recent theory suggests that the strange-looking dinosaurs might have used their nine meter necks to conserve energy. By standing in one spot and grazing from low-level vegetation they could get more for less.
In a new paper published this week in the journal Biology Letters, ecologists Graham Ruxton from Scotland's University of Glasgow, and his colleague David Wilkinson of Liverpool John Moores University, wanted to try and prove this new theory's viability. Using a very simple calculation they were able to evaluate the potential energetic consequences of neck elongation.
"It sounds plausible that a long neck would mean being able to reach more vegetation without moving, so we did a model to see if it would actually work," Wilkinson told Deutsche Welle.
"We can't prove that is what the dinosaurs did, but our findings show that a longer neck would allow them to conserve the energy of having to move around."
Vacuums and sauropods
The scientists draw an analogy between the sauropods and old-fashioned vacuum cleaners which comprised an ungainly body and long tube, thereby making it possible to hoover large areas of a room without having to move the machine.
Basing their maths on the largest of the sauropods, the brachiosaurus, the scientists say they did not only discover that the low browsing theory had legs, but that the length of the neck relative to the dinosaur's body, was pretty perfect.
"If you were trying to design it as an engineer, you would come up with the necks they had," Wilkinson continued.
Because their necks joined their bodies six meters above the ground, they had to be at least six meters long in order for them to be able to drink. The additional three meters, the scientist explained, perfected the picture.
Perfect length
"According to our maths, making the neck seven or eight meters long meant they could save energy by eating on low grazing vegetation without walking about," Wilkinson said. "But if you keep making it longer and longer, the advantage drops off. Something like nine meters is about right."
It is also about the length of fossilized sauropod necks. And however peculiar they might have looked with their tiny heads perched atop their snake-like necks, the creatures stood the test of time well. Larger than any living creature on the planet today, they existed for something in the realm of 100 million years.
"They are ecologically so odd, so huge, but they were hugely successful," Wilkinson said.
The ecologists have been so inspired by their foray into the world of long-necked creatures, that they now plan to take a closer look at giraffes and other animals, dead or alive, who shared the same funny looking feature.
Author: Tamsin Walker
Editor: Cyrus Farivar