Specifically, the reproductive and growth patterns of the dragons in Naomi Novik's wonderful alternate history Temeraire series, parts of which I've been rereading recently. In this version of our history, dragon-riding aviators fight in the Napoleonic wars. These dragons are natural, not magical, beasts, which come in numerous different breeds. They're typically at least as intelligent as human beings but with distinctly draconic personalities. They have an amazing facility with languages; a newly hatched dragon fluently speaks the language (or languages) it heard while in the egg.
In rereading the first two books, I started wondering about the creatures' life cycles. Typically, in terms of reproduction and growth organisms fall into "r-selected" and "K-selected" types. (According to Wikipedia, however, this dichotomy is now thought to be oversimplified, since some species have aspects of both.) An r-selected species chooses quantity over quality—reproducing fast, bearing large numbers of offspring, typically providing minimal or short-term parental care, and hoping a few survive. A useful mnemonic reminds us that R equals "rapid." For example, bacteria, dandelions, and most insects and rodents. K-selected species have few, widely spaced offspring, prolonged childhoods, relatively long lives, and significant parental care. They also tend to be large. Typical K-selected animals include gorillas, elephants, whales, and us.
Novik's dragons look like a typical K-selected species. If not killed by violence or disease, they far outlive a human lifespan. They're huge, most subspecies considerably bigger than elephants. On the other hand, a dragonet hatches not only talking but walking and otherwise self-reliant. And they seem to grow to adult size in a year or so. How do their K-selected traits fit with the precocity and rapid growth? Well, human babies grow faster in the first year than at any other time of life, so there's some precedent to draw upon. And, as mentioned in the Wikipedia article, some creatures (redwood trees and sea turtles are mentioned) combine elements of both reproductive strategies. In addition, Novik's dragons have one other trait that could explain their precocity: They spend a very long time in the egg, sometimes up to six years. Presumably the maturation K-selected mammals undergo after birth happens to dragons between the laying and hatching of the egg.
That hypothesis satisfies me except for one question it raises. How does the eggshell hold enough nutrients to sustain such a long period of rapid growth? Since Novik's dragons are naturally evolved creatures, we can't invoke magic as an explanation. However, the detailed world-building in these novels and the delightful personality of the dragon Temeraire (seen through the viewpoint of his human partner, Captain Laurence, a naval officer drawn, at first reluctantly, into the corps of aviators) make suspension of disbelief smooth and enjoyable.
Here's a forum on Novik's website where fans discuss the biology of dragons, the physics of flight, and other aspects of this alternate Earth:Questions About the Series
Margaret L. CarterCarter's Crypt