Worldbuilding Wednesday: Zlotl Biology

Excerpted from the Encyclopedia Xenobiologica, v43.981.4a, slightly abridged, Ponoma Publishing House, a Yima subsidiary

The zlotl are a sapient bipedal amphibious species, native to the planet Umsaa. They developed spaceflight only recently, but have quickly become known for their prowess in medical science.


Figure 1: Umsaa.

Reproduction and Life Cycle

Zlotl are dimorphous at birth, though true hermaphroditism occurs in roughly 5%, and full conversions between reproductive systems is medically possible. Zlotl lay eggs in clutches of four to seven, and the resulting group of “broodsibs” is the basic unit of family structure. After a few years of parental oversight, the broodsibs are coordinated enough to survive by themselves, rarely staying in touch with parents. Parentage is often socially unimportant, except for high-status dynastic rulers.

Typically, a brood has at least one member predisposed to leadership roles and one predisposed to emotional passivity, but it is unclear whether this is biologically real or merely self-fulfilling cultural narratives.

Zlotl reach maturity at roughly fifteen years (plus or minus two), and live to be roughly one hundred and ten, though medical advances have recently raised average life expectancies nearly two decades.


The most notable feature of zlotl biology is the enormously flexible genome and endocrine system. Without modification, zlotl are fairly homogenous, with only minor ethnic variations across Umsaa. With the right hormonal supplements, zlotl can manifest fangs, claws, fins, bioluminescence, or far more. The full extent of possible changes is unknown, especially with combinatorial explosion among different genes.

The reason for this malleability is still unclear, and research is ongoing. The best-supported theory is that modern zlotl are a confluence of an entire taxonomic family.


The main settlements of Umsaa are either stationary cities on solid ground, or nomadic sea settlements drifting on ocean currents. In rural regions, towns are centered on river deltas and agricultural flood plains.


Figure 2: an elevated zlotl farmhouse.

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