Posted on 05/17/2009 8:09:00 PM PDT by nickcarraway
A new research has suggested that long-necked dinosaurs didn't graze treetops, and were better off holding their necks horizontal, not upright.
According to a report in National Geographic News, lifting long necks at steep angles would have put intense pressure on sauropod hearts, requiring dramatic expenditures of energy to keep blood pumping to the brain.
Sauropods were giant, long-necked, long-tailed, four-legged plant-eaters that lived about 200 to 66 million years ago (prehistoric time line).
Since long-necked modern animals, such as giraffes, tend to browse on leaves in tall trees, paleontologists have assumed that sauropods-whose necks could be as long as 30 feet (9 meters)-must have done the same.
But, Roger Seymour, of the University of Adelaide in Australia, found that sauropods would have spent as much as 75 percent of their bodies'' energy to keep their heads held high.
Most mammals use about 10 per cent of their energy to circulate blood through their bodies. Giraffes use about 18 per cent of their energy to keep blood moving through their long, upright necks.
"Would the increased availability of food in tall trees be worth the cost? This seems doubtful," Seymour said. "It would probably make more energetic sense for (sauropods) to feed with their necks close to horizontal," he added.
By moving their necks side-to-side horizontally, sauropods would have been able to feed on a very large area of plant material without having to move their bodies.
That may not seem like a much of an energy-saving tactic.
But, in animals that may have weighed 30 to 40 tons, the energetic difference between taking a few steps and not taking a few steps may have been as huge as the animals themselves.
Ping
Maybe they stood in water 30 feet deep and ripped something like kelp off the bottom.
I thought the treetop grazing thing was settled science, at least as settled as global warming.
;-)
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Thanks nickcarraway. I think this may have been posted before, a while back, but I'm pinging it because I can't recall for sure, and it's late and I don't want to check. :'( |
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Kinda like when we stand up to fast huh? “Whoo, shouldn’t have gone after that top leaf!”.
Kinda like when we stand up to fast huh? “Whoo, shouldn’t have gone after that top leaf!”.
Kinda like when we stand up to fast huh? “Whoo, shouldn’t have gone after that top leaf!”.
Wow, a triple post and I only clicked once. Oh, well.
But more study will needed to establish whether they had necks or not. The scientific community remains divided on the question.
Well. I certainly KNOW they eat in the treetops. I've SEEN it! Jurassic Park PROOOOVES they ate in treetops.
This composite images shows Diplodocus (left) and Apatosaurus in a variety of extremes of the range of motion of their necks. The data for the neck curvature was determined in the earlier study on neck flexion, but with more attention now given to the post-cervical skeleton.
I wonder if they have taken into account the centripetal forces on blood flow. Sure, if they just stuck their heads up in one place the energy use would be great, but what about a head swinging side to side and then up?
How is this news?
I remember Discovery’s “Walking with Dinosaurs” that came out years ago that showed this.
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