Monarch Skulossus (juvenile) (Patreon)

Adult monarch skulossus are one of the largest animals to ever walk Serina's surface, but they start out as pudgy chicks weighing only about thirty pounds at birth. Of course, emerging so small, a gigantic adult female can produce between twelve to twenty chicks per litter. Chicks are born heavily armoured, and immediately toddle off into thicker undergrowth where larger predators are less common. Their hides are duller and more cryptically coloured as they rely on camouflage as their primary defence, but becomes more vibrant as fewer things can threaten them. Notably, infants are born with bristles covering their body, vestiges of their avian lineage to assist with initial thermoregulation, but this falls out within a few days of birth.

The young have shorter, deeper skulls to tackle tougher and more varied vegetation than the primarily browsing adults. One cannot afford to be selective about their diet when they need to gain nearly two-thousand times their original mass over some thirty years. At the peak of its growth, a young skulossus is putting on nearly five-hundred pounds every month. Scavenging and feeding on insects is not uncommon, as these food-sources are more calorie-rich than vegetation, but they are too slow to hunt and the amount of animal matter drops off as they become far too large to be sustained by insects, and their digestive system becomes more well-adapted to extract energy from plant matter. They particularly consume bones whenever possible to subsist on their calcium, which is vital for their skeletal growth (adults, after all, possess one of the largest skeletons on Serina).

The armour of the juveniles is a necessary defence when they face a plethora of huge predators with bone-crushing jaws and size alone is not enough yet. The various bony spines, knobs, and plates do not grow proportionately and are largely reabsorbed into the body as they mature. In particular, the large spikes lining the flanks and tail are almost completely lost in adults. The tail is used as a last resort club-like weapon in juveniles, but becomes a fat storage organ and display structure in adults, with the lower vertebral processes lengthening to produce the colourful tail fin seen in mature animals. The armour's resemblance to that possessed by adult skuggernauts corresponds to their armoured common ancestor, but this was lost in adult browsing skulossi as they evolved different means of predator defence and became more lightly-built.

While the adults are fully terrestrial animals, with long legs for striding efficiently across the savannahs and prairies of the Serinarctan interior, juveniles have proportionately shorter legs and a much lower build, being more suited for a forest-dwelling, semi-aquatic existence. Juvenile monarch skulossi are common in the upperglades, being naturally buoyant, they are excellent swimmers and feed extensively on aquatic vegetation, often fleeing to water from land-dwelling predators. Juveniles live in creches for protection, often alongside larger herbivorous animals for greater safety. They gradually feed high and higher into the trees as their legs and get comparatively longer. Subadults have an urge to become independent, an instinct to help prevent inbreeding, as they form or join herds with largely unrelated adults.

The illustration represents a juvenile animal, about eight years old, and weighing in at about ten-thousand pounds. It will take another twenty-two or so years for it to reach adult size (sexual maturity is reached well before skeletal maturity, however) at which point it will become virtually untouchable. Only a small number of infants ever reach even eight years old, but those which do have a good chance of reaching adulthood.