1 Embryonic/prebirth (fifty-five to seventy-five days): In captivity, this period of development, which occurs within the confines of the egg, is usually spent in an incubator. However, genetics, diet, health of the mother, and incubation conditions can all play roles in health at this stage. These factors are of concern to breeders and deserve further study by scientists.

      2 Hatchling (birth to about 5 inches long): Newly hatched babies are acclimating to life outside the egg. The first few days are a rest period and then, over the following few weeks, babies learn to drink, find small prey, and develop a routine of basking, eating, and sleeping.

      3 Juvenile (5–13 inches long): Stages 2 and 3 are characterized by ravenous appetite, frequent feeding, rapid growth, and a tendency to mutilate other young dragons, including nipping off tail tips, toes, or other low extremities, when food is insufficient. I’ve seen a hungry 6-inch bearded dragon try to eat its lifelong cagemate, which was only 4 inches long. It couldn’t swallow the smaller dragon, but it did crush the victim’s skull, killing it.Eating and growing are the primary concerns of Stage 3. In this stage, dragons frequently perform arm-waving behavior, a type of appeasement and intraspecies identity display. A social hierarchy based on feeding vigor/assertion and growth develops into two levels: the tough, big, aggressive feeders and the shy, small, “feed after the others” individuals.The primary differences between Stages 3 and 4 are size and behavior. Stage 3 begins when the young dragons reach a length of 5 to 6 inches. Mutilation tendencies toward animals in the same size range continue. By Stage 4, cannibalistic tendencies greatly decrease, as does the frequency of arm waving, especially in males. Dragons grow rapidly and eat a greater percentage of plant matter. A pattern develops: the bigger a dragon grows, the more it eats, so the more it grows, and so on. Social behaviors are still limited and, if enough food is provided, mostly passive.

      4 Subadult/adult: (13–22 inches): Stage 4 lasts through the first three years of breeding activity. This socially interactive stage is characterized by a greater range of social behaviors, which are triggered by sexual maturity. The onset of sexual social behaviors results in well-defined hierarchies, with an alpha male becoming ruler of the roost. Males perform courtship, territorial, aggressive, and breeding behaviors. Females perform slow head-bobbing behaviors or push-ups to reveal their identity. Females also display submissive arm-waving behaviors during breeding. Growth rates at this stage decline because of hormonal changes and the diversion of energy and nutrients away from growth and toward breeding. Dragons achieve their adult length during this stage. The second year of Stage 4 will bring an increase in girth but usually no increase in length. After the onset of Stage 4, bearded dragons normally go through a brumation (winter shutdown period) annually.

      5 Mature adult (fourth year of breeding until five or six years old): A gradual decrease in reproductive rate and little, if any, significant growth is associated with this stage of a bearded dragon’s life, which lasts two to three years.

      6 Old age (usually by six to seven years of age): This stage is characterized by little or no breeding, at least in females. There is no measurable growth. Eventually, old bearded dragons enter a terminal stage of decreased feeding and increased lethargy that, over weeks or months, leads to death. It is wise to cut back on calories (but not all nutrients) with old dragons and pay special attention to providing adequate levels of water as well as comfortable surroundings and stress-free days.