Corona Lagerbeard,A Tabitha McMoggy,B Melon Husk,A Archipelago JonesC and Günther SchlonkD*
This literature review summarises the current body of knowledge concerning Capra stabilis, the even-toed ungulate commonly known as the dahu. The history of its discovery, its physiology, behaviour and evolutionary lineage are discussed.
For centuries, the dahu was considered to be mythic, akin to the jackalope, the wendigo, the drop bear and the tenure-track position. Just a story to amuse children and confuse tourists. A feature of French and Swiss folklore since ancient times, the dahu is said to be a kind of mountain goat with long legs on one side and short legs on the other. These asymmetric limbs allow the dahu to stand perfectly level on the steep mountain slopes it inhabits. Prior to 2018, no credible sightings of a dahu had been recorded since 1838 (coincidentally, the year before the invention of photography). Accounts from before this time are fragmentary and contradictory, which had led biologists to dismiss the dahu as a fabrication.
This paradigm was irrevocably altered in the winter of 2018 by the well-known survivalist, TV personality and urophage Bear Grylls. The inveterate piss-drinker was recording an episode of his show: “Man vs Wild: Ultra-Extreme Apocalyptic Super-Survival” in the Swiss alps when he spotted what appeared to be a mountain goat.1 He briefly remarked that such goats were well adapted to maintaining their balance on steep alpine slopes, before dropping a boulder on its head, and weaving a basket out of its intestines. This episode was unremarkable in the context of Grylls’ work, but an astute viewer of the program observed that the poor eviscerated goat in question clearly displayed asymmetric limb elongation and truncation.
This was the first compelling evidence for the existence of the mythical dahu in nearly two centuries. Regrettably, little remained of the original creature (Grylls consumed its flesh and turned its skin into a “goat-tote”, a precursor to his “sheeping bag”).2 Hordes of intrepid explorers set out into the alpine regions of France and Switzerland, hoping to be the first to snare a specimen of this elusive beast.3 Within weeks, there had been multiple sightings, but no successful trappings. Later studies have revealed the dahu to be an exceptionally cunning and flighty creature, a trait that rationalises its mythical reputation.4
It was Otto von Jägermeister who first managed to snare a live Dahu. This intrepid Bavarian naturalist heeded to the old folk tales to inform his trapping strategy. While his competitors were using nets, bait and tranquiliser darts to no avail, Otto crept up behind a feeding dahu and did his best impression of a horny goat-call. The perplexed creature turned around, immediately toppled over and rolled down the hill into the waiting arms of Otto’s assistant, Guillaume Chèvre-D’Attrapeur. Otto and Guillaume brought their captive dahu back to their lab at Der Universität von Kindergeschichte in Märchenhaft. There, they conducted an anatomical examination.5 Our budget does not extend to licencing Jägermeister’s photographs here, so we’ve commissioned an artist’s rendition of the captive dahu instead (Fig. 1)
Physiologically, the dahu is broadly similar to the alpine ibex (Capra ibex) and the chamois (Rupicapra rupicapra). Its most striking feature is the length of its legs: the dahu has two elongated legs on one side of its body, and two truncated ones on the other. Such crural asymmetry was previously unknown to science, and existed only in the realm of myth. The sidehill gougar (Membriinequalis declivitous) and the wild haggis (Ventriculus caledonii) are reputed to exhibit a similar
asymmetry, but no specimens have been recorded to date. These uneven legs allow the Dahu to maintain a level stance on the steep mountain slopes it inhabits. Consequently, a dahu may only traverse a slope in one direction. Dahu may gain or lose altitude by spiralling up or down a mountain, but cannot turn around without falling over. When a dahu attempts to walk on a level surface, it walks in a circle of fixed radius, as determined by the relative length of their legs. It has been proposed that a dahu stranded in wheat field created the first crop circle, while trying to find its way home. Otto von Jägermeister asserts that a drunken dahu can walk in a straight line, but he has never explained how he knows this.
The dahu population is split into two distinct subgroups: those with longer left legs and those with longer right legs. Some have termed these enantiomeric goats Capra levogyrus/dextrogyrus orDahu senestrus/desterus while others prefer Dahu democratique and Dahu républicaine. The abbreviations L-Dahuand D-Dahu are often used.6When this distribution was observed, some zoologists believed that these groups constituted two distinct subspecies. Another theory suggested that leg length was sexually dimorphic; with males having longer left legs and females the reverse.7 Both theories were debunked in 2021 when the dahu genome was sequenced.8 A team led by legendary geneticist Cedric Franger proved that left and right-handed dahu are in fact the same species. An autosomal gene was identified as a controlling factor in leg length. The wildtype allele “n” produces short legs, while two codominant alleles “R” and “S” cause elongate legs on the right and left side respectively (Fig. 2).
Wildtype homozygoats (nn) are viable embryos, but are abandoned by their mothers shortly after birth. While a high mortality rate is thus incurred, chamois have been observed to adopt nn homozygoats on rare occasions.9 Heterozygoats (nR and nS) are normal dahu. Individuals with an RS genotype have four long, gangly legs. This gives RS individuals a high centre of gravity and poor coordination, which typically causes these individuals to fall down the mountainsides to their death. Finally, homozygous mutants (RR or SS) have two short legs and two enormous ones, which can be up to three times greater in length. These dahu can only survive on cliff faces. Chimeric dahu have been observed, with three long legs, or diagonally opposed long legs. These individuals are also prone to falls, and thus rarely survive long.10
As only Heterozygoats survive to reach sexual maturity, and 50% of their offspring are non-viable, dahu populations grow only slowly. While it is genetically implied that left and right-handed dahu are capable of interbreeding, the act of copulation has not yet been observed.11 A number of theories exist to explain how two dahu, which cannot face the same direction, might conjugate. Most involve a degree of gymnastic contortion on behalf of the male dahu. These theories are collected in Marcel Millefeulle’s excellent book “The Capra Sutra: How Goats Get It On.”12
C. stabilis possesses a unique horn architecture. Most members of the genus Capra exhibit curved horns with single points. Dahu, however, have highly variable and often intricate horns with up to ten points. The purpose of this detailing is not entirely clear, but it is presumed to be a result of sexual selection (Fig. 3).13 Historical depictions of the dahu often omit the horns, perhaps for reasons of artistic laziness. However, it has been theorized that the dahu inspired the design of the Modell 1890, a multitool later known as the “Swiss army knife”.
Another notable feature is the placement of the stomach, which is adjacent to the lungs rather than beneath them. It is believed that this attribute is responsible for the evolution of the dahu’s uneven legs. Julius Child observed rapid mortality in Dahu kept in a flat paddock. Autopsies of the deceased individuals revealed that when a dahu’s torso is inclined more than 10o, gastric acid overflows into the lungs. This incursion converts respiratory tissue into a form of pâté, which is delicious but ineffectual at oxygen uptake.14 To avoid this fate, C. stabilis evolved uneven legs.
The dahu has deeply striated hooves. Compared to those of ibex and chamois, dahu hooves exhibit deep grooves and ridges, which are believed to help them grip wet and icy surfaces (Fig. 4).
When the dahu was first discovered, it was theorised to be a chimeric hybrid of an ibex and a chamois. Again, Cedric Franger’s genetic studies were definitive in the assignment of C. stabilis’s lineage. Franger places the dahu and the ibex as descendants of the archaic Capra vetus (Fig. 5).15 Also related are the chamois (Rupicapra rupicapra) and the Bourgeois (Rupicapra antoinette), which has been extinct since the French revolution. The progenitor of all capra is Pan, the Greek god of the wild and the original horny old goat (Capravetus lascivious).
The genetic distance between Capra stabilis and Capra ibex may be slight, as there are anecdotal reports of dahu-ibex hybrids. No such hybrid has been officially documented, but photographic evidence of ibex with asymmetric legs strongly implies interbreeding of dahu and ibex populations.16 There is fierce debate in academic circles concerning the name for such a hybrid: a dibex or an ihu.
C. stabilis is omnivorous, subsisting primarily on wild onions and alpine snails, but has been observed to consume agricultural crops such as grapes and wheat when these are available. Female dahu supply their young with a thick, creamy excretion from their mammary glands. The texture of this milk has been compared to cheese, and it is apparently delicious, though difficult to obtain.
The social and reproductive lives of dahu remain largly unknown, and significant research efforts are being made on this topic. Studies of the dahu are complicated by its flighty nature, and the inaccesibility of its natve environment.
The discovery of a new mammalian species is always an exciting occasion, even more so when the species in question bears radical differences from its nearest relatives. Zoologists worldwide have been inspired by these events to renew the hunt for other mythic species. Hopefully, these efforts will be met with success, and more remarkable species will be reported in the coming years. We have noted that several companies have chosen to market their products under the name “dahu”, including the makers of ski-boots and a light aircraft. There is an implication in these names that one boot is taller than the other and that the plane can only fly in circles, but we have been unable to confirm these theories.
Notes and references
1 B. Grylls, 2018, MvW:UEASS, S1E2, 17:34.
2 B. Grylls, 2019, MvW, S3E3, somewhere in the middle.
3 “La chasse au dahu” C. Bergerac, 2019, Le Monde, 1/4/2019, 16.
4 “Dahu, The cunning old goat” R. Federer, 2020, J. Mam. Psych. 1, 123–456.
5 “The physiology of the dahu” G. Chevre-D’Attrapeur, O. Jägermeister, 2020, J. Mam. Fizziology, 28(7), 4869–4877.
6 “Nomenclature of chiral goats” C. de Gaulle, 2021, Science, 7, 9.
7 “Sexual dimorphism in the dahu” K. Clovis, 2021, Nature, 8, 10.
8 “The genome of the dahu”, C. Franger, 2021, Genetics, 23, 18.
9 “Homozygoats?” D. Flattenborough, 2022, J. Anim. Sci. 6, 66–69.
10 “Two long legs good, three long legs bad: unstable chimera in C. stabilis” G. Orwell, P. Snowball, 2023, Anim. Pharm. 19, 84.
12 “The Capra Sutra: How Goats Get It On” M. Millefeulle, 2022.
13 “Why are these goats so horny?” J.J. Rousseau, 2023, PNAS, 1, 4.
14 “Respiratory collapse in C. stabilis” J. Child, 2022, J. Anat. 8, 9–11.
15 “The lineage of the dahu”, C. Franger, 2023, Genetics, 1, 602–608.
16 “Dahu-ibex hybrids” D. Funk, J. Annecdot. Bio. 79, 19401–19404.