The Mock Ox

 

Of all the Euathyrmatherian Fauxungulate herbivores that inhabit Athyrmagaia, among the most successful clades of all would have to be Borea's Ruminantiformes. True to their name, the Ruminantiformes have the most well-developed foregut fermentation system of any herbivore on the planet, utilizing both symbiotic, proteinase K-secreting gut microbes and a specially evolved, multi-chambered crop in their thoracic zooids to break down the tough PLA-based tissues of Olekirkophyte foliage back into lactic acid and lactide. Superbly adapted for herbivory, the cranial zooids of many Ruminantiformes almost resemble the heads of ornithopod dinosaurs at a passing glance, with a short, broad three-part beak at the tips of the upper mandible and gnathopods, evolved for cutting or cropping vegetation. They have also evolved the ability to chew, and the internalized lower mandibles and palatine papillae have been modified into mineralized grinding plates. One of the chief clades nested in this highly prolific lineage of herbivores are the quite fittingly named Xenobovidae, a family consisting of both large-bodied heavyweight grazers and lithe, antelope-like sprinters. A trait that sets this particular family apart from other related Ruminantiformes is their possession of ceratopods, a pair of modified limbs at the front of the thoracic zooid that are each tipped with a single enlarged claw. The ceratopods are essentially mobile horns, and are often used for either combat, display, or even both.

 

The second largest and arguably most iconic member of the Xenobovidae family is the diurnal, grassland-dwelling Xenobos borealis, a large-bodied ox-like herbivore roughly equal in height and weight to a domestic dairy cow (Bos taurus) but exceeding it in length. Xenobos borealis, or the "mock ox" as it is more commonly referred to as, is a very common sight in Borea's grasslands, particularly the Western Weave and Central Savannah, as its diet is mostly comprised of various species of Astrogramineae (star grasses). Like most Ruminantiformes, Xenobos walks in an unguligrade fashion, supporting its weight on four-clawed hooves. Aside from its large size, one of the most distinguishing features of Xenobos borealis is its greyish brown body hair, with a black stripe running down from the tip of its upper mandible to the nape of its neck, and an additional white stripe over its eyes and a red stripe on the cheek for males. The posterior sclerites (the keratin plates on the top of the lower abdominal zooid) are ossified and covered in an array of sharp keratinous spines. This appears to have evolved as a defense against predators, as the spiny backside of the animal often discourages carnivores from attacking directly from behind. The ossified core of this armor plating also plays a role in calcium storage, and gravid females recycle this extra calcium to help form the bones of their developing calves. Both sexes possess thick, inward-curving ceratopods that are held forward at a neutral stance. Males (or bulls) have longer and more curved ceratopods than the females (cows), and in both sexes they can be used as effective weapons for self-defense. In the case of bulls, the ceratopods can be used to fight against other bulls to compete for mates.

Like nearly all Athyrmatherians (and EXTREMELY unlike our own bovine mammals), Xenobos borealis is oviparous, though it has altered this method of reproduction in a manner that closer resembles live birth. Xenobos, along with a majority of Ruminantiformes, are semi-ovoviviparous, and rather than laying several eggs that hatch into larvae that couple together post-hatching, impregnated females produce a single, extremely elongated egg that houses four developing quadruplets of the same sex, which couple together as soon as their mandibles develop and partially metamorphose into a single "composite infant" while still in the egg. This quadruplet egg is incubated internally for about 250 days, and when the incubation period is finally complete, the gravid female lays the egg, which breaks open upon impact with the ground much like a mammalian placenta. From there, the newly hatched composite baby (or "calf") is cared for by its mother until it is old enough to live on its own, and rather than feeding her calf from a teat (Athyrmatherians do not lactate), the mother feeds them cud regurgitated from her foregut, simultaneously sharing the essential PLA-processing bacteria with her child. Despite part of their metamorphosis taking place while still in the egg, the composite infant and adult forms of Xenobos fully retain the nearly ubiquitous ability to separate and reattach their body zooids at will.

Xenobos borealis is a very social animal, with cows living in large maternal herds that travel and eat together. These maternal herds are highly altruistic, and the cows will occasionally even take turns looking after each other's calves. When the herd is threatened by a predator, the herd members will arrange themselves in a circular defensive formation and surround the calves and pregnant females, their spiny, armored backsides facing outwards to fend off the attacker. They are also migratory, spending a majority of spring and summer and in the grasslands and savannah but moving to the xeric shrublands further south during the fall and winter. Bulls, however, live largely solitary lives, and the only time bulls ever meet together is during the mating season in spring, where they will gather near herds of cows and compete for mates via intraspecific combat. Battles between Xenobos bulls tend to be rather gruesome, as it usually involves the two opponents trying to forcefully decapitate one another using their ceratopods until either one of them yields or gets decapitated. While Xenobos are naturally capable of dropping their own heads at will, having their heads be forcefully removed can potentially be devastating to their livelihoods, since it may irreversibly damage the nerve conduits or even break the coupling joint that connects the head to the shoulders. Due to this, if one bull ends up losing his head during a duel, it often ends up being his last.