In this paper, I will not only present the first summary of Swenson’s observations to see the light of day in nearly 250 years, but demonstrate that they constituted a cautionary tale. Had they been appreciated at the time, New Utah’s agricultural collapse might well have been prevented, and New Utah would not now be dependent upon selenium supplementation from Maxroy’s Purchase. As it is, they attest an exciting and possibly unique biological adaptation to extreme conditions and highly variable climate. I present it here at this conference in the hope that xenobiologists from every world will review this data, as it is directly relevant to questions of how life begins on and propagates across many worlds.
The Planet of the Apes
Swenson observed and recorded dozens of now-extinct animals on New Utah, but in this paper I will focus on several related species divided into two groups herein classified as Swenson’s Greater Apes and Swenson’s Lesser Apes. Swenson himself did not refer to them as “apes” at all; he was quite clear that despite their physical appearance, they were not even mammalian, let alone Earth primates. However, their general hirsute appearance, bipedal locomotion, direct manipulation of their environment with arms and hands, and absence of tails made them appear ape-like to early settlers. The chief physiological distinction between the two groups is that the Lesser Ape species are six-limbed and bilaterally symmetrical, with two legs and four arms, while the Greater Apes (in general, as we shall see below) are not, possessing only three arms.
Swenson viewed these creatures directly, as well as conducting detailed interviews with farmers and construction workers. Early observers presumed that there was only one species of Swenson’s Ape, but that it was highly variable in size and color. The presumption was natural. The animals lived in colonies widely dispersed among the vast “grass” marshes of the Oquirr delta, about which more later. Each colony included animals ranging in size from that of a newborn human infant, to some (at the largest) approaching two meters in height. The tallest individuals were generally white in color, and the smallest brown or black, although this was not always the case. Colors included white, brown, black, and occasionally striped individuals, locally called “zebras.”
Interestingly, Swenson soon determined that these size and color variations actually corresponded to separate species, not size and color variations within a species. Further, all colonies appeared to be multi-species, and all apes appeared to live in colonies. Within each colony, one species, brown in color, dug and maintained elaborate tunnel systems, with galleried nesting dens. Another species engaged in rude cultivation, planting and propagating the “grasses” in exposed mud flats. A third species “stood guard” at the colony perimeter, making gestures quickly understood as threatening by early settlers—this species proved most troublesome to settlers, at is possessed sharp, chitonous, cutting spines which it used to fatal effect until colonists began shooting them on site. Another species, more massive than the others, burrowed water diversion channels that created new mud flats for planting. Swenson believed that the two species of Lesser Apes, named Swenson’s Marmosets and Swenson’s Shrews, were commensals—animals that lived only in association with the colonies, but had no specific role within it. Both scavenged food and material wastes and created smaller sub-colonies ringing the main dens. They may have been tolerated for their “alerting” function, as they became quite agitated on the approach of any person or animal. The largest species, usually white, but sometimes black, in color, served no visible function, although it prowled widely within the colony itself and throughout the surrounding “fields.”
Swenson found the apparent stability of this “social symbiot” colony structure to be remarkable, because the colonies were few and far between, none of them large, with most colonies including no more than a few individuals of any one species. How, he wondered, did their populations remain viable?
Zebras, Mules, and Truth Stranger than Fiction
Swenson noted that, on various occasions, each species had been observed carrying what were clearly offspring, but no offspring had ever been observed among the “zebras,” which were also least numerous. Swenson initially presumed that “zebras” were sterile hybrids, often called “mules,” the result of a chance mating between two Ape species. However, the fact of interspecies generation of offspring aside, it became clear to him that appellation “mule” was a misnomer— a fact with profound implications for understanding the reproductive agenda of all Swenson’s Apes in general.
Swenson found that “zebras” were not, strictly speaking, hybrids. Hybrids form from the fusion of gametes (egg and sperm) from two species to form a single zygote (fertilized egg) that will develop if and as possible. For example, an actual hybrid mule is the offspring of a male donkey, which has 31 pairs of chromosomes, and a female horse, which has 32 pairs. The resulting offspring has 63 chromosomes. This odd number of chromosomes results in an incomplete reproductive system, which is always sterile in males, and usually sterile in females.
Swenson’s Ape crosses are not “mules” in this sense. Rather, they are chimeras. Chimeras result from the physical mixing of cells from two independent zygotes (fertilized egg cells). “Chimera" is a broad term, applied to many different types of cell mixing. Although cross-species mixing is possible among species that are closely related and share similar developmental physiology, most chimeras result from the mixing of cells within a species. Chimeras can often breed, but the fertility and type of offspring depends on which cell line gave rise to the ovaries or testes. Intersexuality and true hermaphroditism may result if one set of cells is genetically female and another genetically male, and as we will see, this is nearly always the case in Swenson’s Apes.
Nevertheless, we can use the cross-species equid analogy to clarify how chimeras differ from hybrids. As stated, crossing a male donkey with a female horse produces a hybrid mule. That is, one sperm of a donkey fertilizes one egg of a horse, resulting in a mule that shares the DNA and characteristics of both parents. It gets long ears from Dad, a short, glossy coat from Mom, and a DNA test of either its ears or its coat would show DNA from both parents.
A chimerical animal would result if one fertilized egg of a donkey (with both male and female donkey parents) were mixed with another fertilized egg of a horse (which had both male and female horse parents). Such an animal would develop so that some of its organs were “pure” horse (with 32 pairs of chromosomes and 100% horse DNA), while others were “pure” donkey (with 31 pairs of chromosomes and 100% donkey DNA). In addition, depending upon how the growing cell lines migrated, the animal’s coat might have patches of shaggy, grey donkey hair alternating with patches of slick, brown horse hair. A DNA test on such an animal would only show the DNA for the specific cell type and location tested. The DNA for the shaggy, grey parts of the coat would be pure donkey; the DNA for the slick brown parts of the coat would be pure horse. To have the “full” genetic picture for this creature, you would have to draw DNA samples from multiple locations. Notably, in Swenson’s Ape crosses, classic chimerical Blaschko's lines (fur striping) occurs, with the colors showing the boundaries of the cell lines.