High C/N ratio (not low-energy content) of vegetation may have driven gigantism in sauropod dinosaurs and perhaps omnivory and/or endothermy in their juveniles
Article first published online: 11 DEC 2012
© 2012 The Authors. Functional Ecology © 2012 British Ecological Society
Volume 27, Issue 1, pages 131–135, February 2013
How to Cite
Wilkinson, D. M., Ruxton, G. D. (2013), High C/N ratio (not low-energy content) of vegetation may have driven gigantism in sauropod dinosaurs and perhaps omnivory and/or endothermy in their juveniles. Functional Ecology, 27: 131–135. doi: 10.1111/1365-2435.12033
- Issue published online: 28 JAN 2013
- Article first published online: 11 DEC 2012
- Manuscript Accepted: 17 OCT 2012
- Manuscript Received: 15 JUN 2012
- plant biochemistry;
- Sauropod dinosaurs were the largest terrestrial animals ever, and the combination of selective pressures that might have lead to such extraordinary sizes has long been discussed.
- Here, we argue that a previous suggestion that large size may be a response to unusually high C/N ratios in available plant foods has been prematurely discarded. C/N ratios were likely to be high during much of the Mesozoic, and C/N ratio is entirely different from gross energy density as a measure of the value of a plant as food. In addition, we use recently published allometric equations for herbivore nitrogen and carbon use to make tentative calculations which suggest that if Mesozoic C/N ratios were greater than extant ones, this would have selected for one of two strategies: gigantism in ectothermic herbivores or endothermy (and selective foraging on high N material) in very small herbivores.
- We speculate that smaller-bodied juvenile sauropods might have had a broader omnivorous diet and/or had higher mass-specific metabolic rates than adults. The former is potentially testable by changes in dentition; the latter matches evidence of high growth rates of juvenile sauropods.