 The documentary "Walking with Dinosaurs" portrayed a mother "Diplodocus" using an ovipositor to lay eggs, but it was pure speculation on the part of the documentary author.For "Diplodocus" and other sauropods, the size of clutches and individual eggs were surprisingly small for such large animals.This appears to have been an adaptation to predation pressures, as large eggs would require greater incubation time and thus would be at greater risk.