April 1, 2009

Old Belief About Long Necked Dinos Proved Untrue

A lovingly-held conviction about the long-necked sauropods, the gargantuan dinosaurs adored by their depiction in monster movies and by children, is most in all probability false, a dino expert stated on Wednesday.

At the height of the reign of the gentle giant, many sauropods' evolved necks of astonishing length, like the 29.25 feet in the case of the Mamenchisaurus, who lived in the Late Jurassic period 150 million years ago.

Belief had held that leviathans operated their long necks like present day giraffes. They used their necks to eat leaves on the top of the forest canopy, out of reach for other herbivores.

Unfortunately, this is not true, notes research published in Biology Letters.

It says that the sauropods preferred to eat horizontally, instead of vertically, because it took less energy to do so.

Australian biologist Roger Seymour conducted a simulation of how much blood pressure a sauropod would require to use its head vertically.

He then determined how much power the creature would need to disperse this blood through the body at this high pressure.

"It would have required the animal to expend approximately half of its energy intake just to circulate the blood," says Seymour.

"A vertical neck would have required a high systemic arterial blood pressure. It is therefore energetically more feasible to have used a more or less horizontal neck to enable wide browsing while keeping blood pressure low."

The Barosaurus, who had a neck similar to the Mamenchisaurus, would require a heart that weighed five percent of its entire weight to push blood to the neck and brain, says a 2000 study.


Image Caption: Mamenchisaurus. Courtesy Wikipedia


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