The long necked sauropod dinosaurs were the largest land animals ever to walk the Earth – but why were they so large? One possibility is that it somehow involved the nature of the plant food they eat, as David Wilkinson (co-author of the paper "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." David M Wilkinson & Graeme D Ruxton 2012) explains in this interview with Robbie Wilson. Wilkinson, D. M., Ruxton, G. D. (2012), 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. doi: 10.1111/1365-2435.12033 http://www.functionalecology.org/view/0/summaries.html#wilkinson http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.12033/abstract