The Unths, so named for the loud sighing sound that accompanies each heavy footfall, will migrate in herds to their calving grounds to the north in the spring. Herds can number about 200 individuals, and their nervous energy is almost palpable. Most of the individuals during spring migrations are of breeding age and many display the distended bellies of pregnancy. Some winters can be hard; the number of young reduced and all the herd members appearing underweight. Even so, they can be an impressive sight treading through the sedge.These creatures rut in the fall. The bulky, 6-meter-tall Unths, tails and backs filled out with their summer's stored fat reserves, cluster in pre-courtship groups. Because there is only one sex among them, the only members of a herd exempt from the ritualistic displays are the very young, the sick, and the aged. The remainder of the individuals are jabbing their tusks into the snow and earth or stamping about trumpeting. This bulging, which emanates from the eight openings on their flanks, is a deep, beautifully four-toned peal, rich with pained desire. It is easily heard for miles around.
Two large Unths can engage in the preliminary bio-light flaring of ritual combat. Standing in place, they rotate rapidly, throwing up clods of snow and earth and pinging loudly. Abruptly, they will stop and face each other, tossing their heads and scratching the ground with their tusks. Sometimes mild pushing matches and tusk-clashing contests will ensue; moments later, they will begin rotating again with renewed energy. The sounds of their combat echoes in the frozen air.This pattern will repeat itself until one of the individuals lowers its head in defeat, or charges. Whatever is the triggering element in the threat display (one certainly would not call it love), it is sufficient to create a mating pair. For copulation to occur, each partner has to withstand, and match, its potential partner's aggressive posturing. Combat is the final test of an Unth mate's compatibility and, it is believed, a necessary element of the animals' sexual stimulation. Combat seems to release pheromones from both individuals that activate the urge to copulate.
There are many threat displays, many of which end in incompatibility. Sometimes, if combat ensures, the loser will be injured or too tired to engage in sex; in these cases they are left where they drop. More often, though, the two individuals will copulate, creating offspring bred for strength and hardiness. The fall rut lasts for about three weeks, during which time most individuals participate in at three combats. Afterwards, the herds move on to the wintering range. Calving will occur in the middle of spring.
Clearly, during the spring, the boisterous Unth herds feel the excitement of seasonal rebirth; of the pleasure of their cold-stiffened hides and joints flexing more easily, and of the irresistible forces of reproduction that push them across the barren tundra. Filling the air with their distinctive hollow sonar, the Unths walk 10 or 12 abreast toward their ancient calving fields.Oddly, during their migrations, if herds encounter a mummy-nest, they split to avoid this particular obstacle in their path. The reason for this remains unknown.
Herds can travel for several weeks. Every few days the Unths will come to a halt on finding a field that is rich in their forage, snowbulbs. Using their tusks, the Unths turn over acres of topsoil to get to the plants, which they suck dry with their long feeding tubes.Eventually, after a number of weeks, the Unths will reach their spring destination, a plain just a few kilometers from the glacier's wall. There appears to be no difference between this part of the tundra and any other, yet the weary Unths seem relieved and content. Ever vigilant against arctic bolt-tongues, skewers and other predators, they proceed to scoop out large cavities in the ground that will receive their young. Into these cavities the Unths regurgitate large quantities of snowbulb pulp acquired from a nearby field. The pulp will solidify and provide an edible, cushiony nest-lining for the active infant Unths.
Soon the air is filled with the sounds of birthing. For days pings, groans, and sighs bounce early off of the nearby glacier and carry for miles into the open tundra. The breeding ground becomes a noisy nursery for scores of tiny, tuskless Unths. Dutiful parents go in shifts to gather food for the demanding infants. The activity and noise are ceaseless, and through it all it is behavior that has not changed for hundreds of centuries.
The young Unths and their giant parents play and nuzzle at the edge of the ice. The adults will protect the young from any potential threats.