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How did the dinosaurs get their neck as long as that?

By Catholic Online (NEWS CONSORTIUM)
February 24th, 2013
Catholic Online (www.catholic.org)

The dinosaurs known as sauropods were the largest animals to ever walk the earth. These leafy green eaters had by far the longest necks of any known animal, reaching up to 50 feet in length, six times longer than that that of the modern giraffe. How did the sauropods evolve necks longer than any other known creature on earth?  Scientists say this was largely due to the creatures' mostly hollow neck bones.

LOS ANGELES, CA (Catholic Online) - "They were really stupidly, absurdly oversized," researcher Michael Taylor, a vertebrate paleontologist at the University of Bristol in England says. "In our feeble, modern world, we're used to thinking of elephants as big, but sauropods reached 10 times the size elephants do. They were the size of walking whales."

In order to discover why the sauropods' necks were so long, scientists analyzed other long-necked creatures and compared sauropod anatomy with that of the dinosaurs' nearest living relatives -- birds and crocodilians.

"Extinct animals - and living animals, too, for that matter - are much more amazing than we realize," Taylor told LiveScience. "Time and again, people have proposed limits to possible animal sizes, like the five-meter (16-foot) wingspan that was supposed to be the limit for flying animals.

"And time and again, they've been blown away. We now know of flying pterosaurs with 10-meter (33-foot) wingspans. And these extremes are achieved by a startling array of anatomical innovations."

Adult bull giraffes currently have the longest necks, capable of reaching about eight feet long. No other living creature exceeds half this length. For instance, ostriches typically have necks only about three feet long.

The largest land-living mammal of all time, inclusive of extinct breeds was the rhino-like creature Paraceratherium, which had a neck maybe 8.2 feet long. The flying reptiles known as pterosaurs could also have surprisingly long necks, such as Arambourgiania, whose neck may have exceeded 10 feet.

The necks of the Loch Ness Monster-like marine reptiles known as plesiosaurs could reach an impressive 23 feet.

Taylor and his colleagues in their research found that the neck bones of sauropods possessed a number of traits that supported such long necks. Air often made up 60 percent of these animals' necks, with some as light as birds' bones, making it easier to support long chains of the bones. The muscles, tendons and ligaments were also positioned around these vertebrae in a way that helped maximize leverage, making neck movements more efficient.

Sauropods also had extensive neck vertebrae, up to 19. In contrast, nearly all mammals have no more than seven, from mice to whales to giraffes, limiting how long their necks can get.

"Sauropod heads are essentially all mouth. The jaw joint is at the very back of the skull, and they didn't have cheeks, so they came pretty close to having Pac Man-Cookie Monster flip-top heads," researcher Mathew Wedel at the Western University of Health Sciences says,

"It's natural to wonder if the lack of chewing didn't, well, come back to bite them, in terms of digestive efficiency. But some recent work on digestion in large animals has shown that after about three days, animals have gotten all the nutrition they can from their food, regardless of particle size.

"And sauropods were so big that the food would have spent that long going through them anyway," Wedel said. "They could stop chewing entirely, with no loss of digestive efficiency."

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