Motie

Moties are the human name for the alien species which inhabit the Mote system. Their defining factors are their asymmetrical anatomy, their genetically hardwired reproductive rate, and their instinctive specialization, which makes each caste innately expert at the jobs they are bred for.

Physiology
Inhabiting the planet Mote Prime and most of the habitable orbiting bodies in Mote System, as well as many artificial orbiting constructs, the Moties' primary distinguishing physical feature is their specialization into castes. Castes mentioned in the chronicles include Mediators, Engineers, Masters, Warriors, Doctors, Runners, Porters, Farmers, and Meats. All of these castes are in the entourage of a Master. Feral forms have also been observed. Engineers use the semi-intelligent Watchmaker caste (called "miniatures" or "brownies" by the crew of MacArthur) as mobile tools. Where a human can to a greater or lesser degree carry out similar tasks, a Motie of a given specialization performs a single function at a high level with no training. Moties alternate between being male and female. A female Motie will revert to male after giving birth, changing back to female after a time. At some point the female must become pregnant again or else the hormone imbalance will kill her. This life cycle naturally forces Moties to become pregnant whenever possible. Although the original four-armed symmetrical Motie body plan still exists, the typical member of the species inherits an ancient asymmetrical mutation. Most Moties have two right arms for delicate manipulation and a much heavier and stronger left arm. An equivalent left-handed form with two human-scale left arms and a heavy right arm also exists. The gripping hand has only three large fingers, while the other two smaller hands have six each — four fingers and two opposable thumbs. By analogy with humans counting in base-10, supposedly as a result of having ten digits, the Moties count in base-12 numbers to match the combined digits on their right hands. The strong gripping arm also attaches to one side of the head for greater leverage. Moties have no spine, instead developing three bones which perform a similar function. During first contact with humans, the Moties found the spine to be of great interest.

Culture
Masters command the loyalty and obedience of groups of other kinds of Moties, such as Engineers, Warriors, Doctors, etc. However they are not good negotiators. Mediators were created as sterile hybrids of the white Masters and brown Engineers to minimize the number of wars between rival Masters. Mediators will always obey Masters, so they cannot themselves change the direction of Motie civilization, but they have considerable latitude to do their job. There is no monetary economy as such, but Masters barter prestige, material goods, etc. A few sterile Masters (unlikely to attempt a takeover for their children) are designated as Keepers and given control of the Museums where knowledge is carefully stored to aid recovery after collapse. When a civilization is doing well, alliances of Masters can cooperate to achieve great things, but the urge to reproduce always causes the alliances to break down, usually resulting in catastrophic wars.