Grisler

Bumblebears, though very fierce, are not the largest carnivores of the Serinaustran steppe, 250 million years post-establishment. They may have four weight-bearing limbs, but their forearms are inflexible, and so their opportunities to remain competitive at larger sizes have been few; these larger bumblebadgers are outliers, not the average. But there is another quadruped bird here. The ornkeys, with jointed forearms, became four-legged through a long, slow process of neoteny, for their ancestors the changelings - or metamorph birds - had free-living, crawling larva which pulled themselves about the ground with their undeveloped wings. New muscles formed to facilitate this locomotion as they grew larger; the shoulder blades angled backward, taking on a mammal-like position. And they improved on the bumblebadger's now comparatively crude form of walking, with front legs each as flexible as their hind ones. 

Ornkeys first evolved as forest animals. Small and fast, they leapt from branch to branch in treetop habitats, and used their newfound arms to swing from vine to vine. But inevitably, some changed. When fruit was less abundant, some fed on leaves, and in turn some grew bigger stomachs to better break down less nutritious meals. Bigger stomachs led to bigger bodies, and so the orkeys came down to earth. 35 million years ago, the lorilla was among the first to dwell on flat ground. It was the ancestor of the most terrestrial of all the ornkeys, the serezelles, rendered thin and swift by a need to outrun their predators. But this was just one branch of the family tree. As the serezelles were growing nimble, the ursers were becoming robust. Slower than the serezelles, they defended themselves with strength. They were broadly omnivorous, feeding on plants as much as any small animal they could catch, and their beaks were broad and capable of powerful crushing to break apart food into manageable portions. Some of them, too, became grazers - big, well-defended ones, moving singly as their delicate cousins leapt around them in herds. And as the circuagodonts, specialist grazing molodonts, have since edged out most serezelles from their former roles in the ecosystem, ursers still remain, their broader diets and aggressive tendencies keeping them competitive. While serezelles were most diverse in the north, on Serinarcta, ursers are most successful on the cool southern continent, where the biggest of them all is now found. It is Serinaustra's largest land predator, even if - due to its sheer size - it is much more often a remorseless thief of other predators than an active hunter itself.

The grisler is a gigantic ornkey endemic to the southern steppe near Serina's south pole, weighing up to 9,000 lbs and standing 10 to 11 feet high at the slope of its back. Slow moving and bad-tempered, it has poor eyesight but a strong sense of smell. It strides over short, cool grasslands with the paired claws of each forearm folded back along its wrists, and around half of its diet - despite its carnivorous abilities - is still grass and vegetation. It digs up roots with its claws and devours foliage wholesale in its wide beak, which is lined with comb-like keratin structures - pecten - that clip grass efficiently. Smaller predators give it a wide berth, for one well-placed swing of its arm will snap even the largest bumblebear's back. And its strength is not just defensive. The grisler is always sniffing around, looking for scent cues for a more favorable meal, and it hones in on carrion, even from before an animal dies by responding to the noises of other predators as they hunt - sometimes even rushing in and carrying off the prey before the attackers have even finished killing it, finishing the job itself. Around meat the grisler becomes a glutton, a savage glint in its eye as it dismembers carcasses limb from limb as if they were made of cardboard and tissue paper, sloppily consuming nearly every part of the body until the silvery plumage of its head and neck is stained a grisly red. Nothing dare interrupt it, for it is so much larger than anything around it that it has no enemies of its own. There is no winning against the grisler - all other hunters can do is be quicker. They must eat their kills, or carry them far away, before this slow but persistent, inveterate super-scavenger arrives to meet them. There is no other alternative. The grisler, the frigid south's true king, will always come for its fill.