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Biol Lett. Jun 23, 2009; 5(3): 317–319.
Published online Apr 1, 2009. doi:  10.1098/rsbl.2009.0096
PMCID: PMC2679936
Raising the sauropod neck: it costs more to get less
Roger S. Seymour*
Ecology and Evolutionary Biology, University of Adelaide, Adelaide, South Australia 5005, Australia
*Author for correspondence (roger.seymour/at/adelaide.edu.au)
Received February 5, 2009; Accepted March 11, 2009.
Abstract
The long necks of gigantic sauropod dinosaurs are commonly assumed to have been used for high browsing to obtain enough food. However, this analysis questions whether such a posture was reasonable from the standpoint of energetics. The energy cost of circulating the blood can be estimated accurately from two physiological axioms that relate metabolic rate, blood flow rate and arterial blood pressure: (i) metabolic rate is proportional to blood flow rate and (ii) cardiac work rate is proportional to the product of blood flow rate and blood pressure. The analysis shows that it would have required the animal to expend approximately half of its energy intake just to circulate the blood, primarily because 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.
Keywords: dinosaur, sauropod, blood pressure, circulation, neck, feeding height
Articles from Biology Letters are provided here courtesy of
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