Some sauropods really did hold their long necks high

Jun 03, 2010 by Lin Edwards report
Sauropod dinosaur Euhelopus zdanskyi. Image: Wikimedia Commons

(PhysOrg.com) -- A new study suggests the long necks of sauropod dinosaurs really were held high, in spite of theories suggesting they were more likely to keep their necks low because of the very high blood pressure resulting from the long distance from heart if they lifted their heads.

The sauropods were the among largest dinosaurs and included well-known species such as the Brachiosaurus, Brontosaurus (now called Apatosaurus) and , which had very long necks to extend their reach. Many scientists have for decades thought they held their necks low to extend their reach horizontally rather than vertically because of the energy that would be required to hold their necks high. In some sauropods the neck could be over 10 m long. More recently there has been controversy, with other scientists thinking that during food shortages holding their necks high to grab food would be worth the energy expended.

The study was carried out by functional morphologist Andreas Christian of the University of Flensburg in Germany, and concentrated on fossils of Euhelopus zdanskyi a mid-sized Early Cretaceous that lived around 112-130 million years ago. It weighed a moderate (for a sauropod) 3,800 kg, with its head and neck weighing more than 210 kg. It measured 11-12 m from head to tail, and the distance from the base of the neck to the nose was about 4.6 m.

Christian calculated the stresses that would have been felt by the in the sauropod’s neck joints, and found the most energy-efficient pose would have been to hold its neck straight and inclined at about 45 degrees above horizontal, rather like a modern-day giraffe. He also calculated the energy costs for walking given distances and compared them to the energy required to raise the neck, and the energy expenditures for maintaining a high for five minutes of high browsing.

The results of the calculations showed that even though a lot of is required to pump blood to such heights, from an inclined pose less work would be needed to hold its neck vertically to graze for up to half an hour than it would need to move their large bodies 100 meters to look for food. The findings were also true for the much larger , and may be true for some other sauropods.

Chrisian said the sauropods may have used their necks differently depending on the distribution of food and the kinds of vegetation, and during food scarcity would have found the ability to extend their reach vertically advantageous if not essential.

The findings were reported on June 2nd online in the journal Biology Letters.

Explore further: Mammoth and mastodon behavior was less roam, more stay at home

More information: Andreas Christian, Some sauropods raised their necks—evidence for high browsing in Euhelopus zdanskyi, Biology Letters, Published online before print June 2, 2010, doi:10.1098/rsbl.2010.0359

Related Stories

Long-necked dinos didn't reach for the skies

Mar 31, 2009

A fondly-held belief about long-necked sauropods, the giant four-footed dinosaurs beloved of monster movies and children, is most probably untrue, a dino expert said on Wednesday.

Did dinosaurs hold their heads up?

May 27, 2009

Some dinosaurs may have held their heads up, like a giraffe, rather than in a more horizontal position, University of Portsmouth scientists report today.

'Giraffe of the Mesozoic' Discovered

Sep 08, 2009

(PhysOrg.com) -- A creature dubbed a "Giraffe of the Mesozoic" has been discovered in China. The animal, with its giraffe-like long neck and long forelimbs is the first well-preserved Early Cretaceous brachiosaurid dinosaur ...

Skull study sheds light on dinosaur diversity

Sep 15, 2005

With their long necks and tails, sauropod dinosaurs—famous as the Sinclair gasoline logo and Fred Flintstone's gravel pit tractor—are easy to recognize, in part because they all seem to look alike.

Recommended for you

Radar search to find lost Aboriginal burial site

17 hours ago

Scientists said Tuesday they hope that radar technology will help them find a century-old Aboriginal burial ground on an Australian island, bringing some closure to the local indigenous population.

Archaeologists excavate NY Colonial battleground

Jul 19, 2014

Archaeologists are excavating an 18th-century battleground in upstate New York that was the site of a desperate stand by Colonial American troops, the flashpoint of an infamous massacre and the location of the era's largest ...

User comments : 12

Adjust slider to filter visible comments by rank

Display comments: newest first

magpies
3 / 5 (1) Jun 03, 2010
giraffe style?
otto1923
3 / 5 (1) Jun 03, 2010
giraffe style?
"rather like a modern-day giraffe."
-yeah. Giraffe style.
Djincs
1 / 5 (4) Jun 03, 2010
"in spite of theories suggesting they were more likely to keep their necks low because of the very high blood pressure resulting from the long distance from heart if they lifted their heads."
Ok some scientists just amaze me, when they lift their heads the blood presure is high? This is really wrong, it is the oposite, when they lower their head the presure goes up, with giraffes we have the same case.....
these days pseudo science is everywhere!
pauljpease
5 / 5 (2) Jun 03, 2010

Ok some scientists just amaze me, when they lift their heads the blood presure is high? This is really wrong, it is the oposite, when they lower their head the presure goes up, with giraffes we have the same case.....
these days pseudo science is everywhere!


Actually, I think they are right. The long blood-filled neck acts like a column of water. The taller the column the higher the pressure. It's kind of basic physics.
Djincs
1 / 5 (2) Jun 03, 2010
No there is no logic in this, the further from the heart you go the lower is the presure this make blood to move from the heart to the other organs, this animal should have had a big arteries to pomp the blood that further.
Make the analog with your legs when they are horizontal or vertical but upside down
Ravenrant
2 / 5 (1) Jun 03, 2010
Yeah they hold their heads up, who wouldn't have thunk. And I would bet they DON'T hold their tails up like they think right now . The depictions in Jurassic Park look so wrong.
Grallen
4 / 5 (2) Jun 03, 2010
When they raise their head the blood pressure in their heads would drop, and in the body it would raise slightly.

Their body will react to the lack of blood in their head and raise over all blood pressure to make sure their brains receive oxygen.

Ever feel your heart start racing when you get up off the couch?
malapropism
5 / 5 (1) Jun 03, 2010
No there is no logic in this, the further from the heart you go the lower is the presure this make blood to move from the heart to the other organs, this animal should have had a big arteries to pomp the blood that further.
Make the analog with your legs when they are horizontal or vertical but upside down

No, pauljpease is correct - the analogue is not your legs held vertically upright while you are balanced on your shoulders but a barometric column e.g. of Mercury. The pressure is higher to hold a greater column of liquid up the vertical column (this is the pressure in the bulb - analogous to the animal's heart). The pressure is not that felt in the extremities (dino's head, your feet) but in the main reservoir doing the "pushing up" work, such as is measured by a sphygmomanometer.
Djincs
not rated yet Jun 04, 2010
No, the presure is higher in a vertical column but the head is at the top of that column, you have two forces one push the blood upword, and the other is gravity, when the head is low the gravity is off and the force that push is uncompensated => the presure is high...
is it so hard to get it...good!
Djincs
not rated yet Jun 04, 2010
Or maybe they are trying to say that for the blood to reach the head the animal have to raise their presure as a whole in their body..this make sense
Djincs
not rated yet Jun 04, 2010
Now I see Grallen has get this....ok, the peace in the univerce is restored.
ArcainOne
4 / 5 (1) Jun 06, 2010
It is basic biology, when the heart starts beating harder blood pressure goes up, this also expends more energy. When these dinosaurs raise their head the heart would have to beat harder to insure that blood flowed up the incredibly long neck. The article addresses the question which asks would this be a practical common behavior for this creature to raise its head high.