Dinosaur eggs have featured on here once or twice, but I’ve never done much more than mention them in passing with the odd decent photo. This is at least in part because they don’t normally impinge much in my fields of work and as such, I’ve never learned that much about them in detail so don’t have too much to pass on. Nevertheless, they are worthy of a bit more attention than I have managed in the past and there has been a minor spate of egg based stuff coming out recently.
Most importantly of course, eggs can, on occasion, house fossilised embryos. These of course being exceptionally young animals tend to have some things poorly preserved (like skulls) or completely absent (like ribs), and can look quite different to the adults. Thus, even when you actually have an embryo in the egg, it’s not always entirely clear to which animal it truly belongs. Still, such finds do of course provide incredible information about the developmental biology of dinosaurs and when the species is known, you get the possibility of obtaining a growth series of everything from an unhatched juvenile right the way through to an adult. That’s quite amazing, and quite impossible without eggs.
In some cases we do know quite a lot about eggs and nests. Thanks to the presence of embryos we can tell which eggs were produced by which taxa. The nature of the nests can reveal something about behaviour and biology as well. Some nests seem to have the eggs produced in pairs, this fits with a troodontid known with a pair of eggs inside the body, suggesting that two eggs developed at a time in these dinosaurs and then were laid as a pair (presumably one from each ovary), and of course also suggests that these eggs were laid over a period of time like birds, and not spat out in one go like crocs or turtles.
Understanding such things (which taxa laid which eggs, how they grew and changed, how nests were created or looked after) can provide real information about dinosaur biology that cannot be gained or accurately inferred from other data. Ultimately more complex and interesting data such as the number of eggs produced by a given animal in a season or year, or how many animals nested in a locality at a time providing population data and significantly adding to our understanding of ecology and sociality in these animals. There is more to come, and I look forward to seeing it, even if it may be quite some time away.