The ups and downs of biwolves
While herdstalkers' hegemony is put on the spot by a carnivore radiation of ducktails, geotters are facing an internal conflict: thanks to a simple but revolutionary body plan, a new lineage of biwolf is driving its ancestral relatives towards extinction, too much specialized to survive a changing world.
With the disappearance of its habitat and its favorite prey, the Scrubring biwolf has nearly faced extinction in the past, followed then by a comeback. Its only descendant that survived close to present is the scansoria (Lutrofelis deserticus).
This species was able to survive by expanding its range in the Everdry plateau and by changing its diet preference, feeding mostly on ground tyrants. It's no larger than a wildcat, half the size of its ancestor. During the driest periods of the year, this small carnivores typically aggregated near the few brackish ponds of this harsh region.
While food is still abundant, scansorias have recently died out, with no successors.
The cause of this extinction is attributed to sheardogs, a revolutionary group of biwolves: at first sight, they are anatomically identical to archaic clades. In reality, sheardogs possess a weaker (but faster) bite: carnassials are elongated, more useful for cutting meat than breaking bones. They are also fully digitigrade, unlike their semi-digitigrade relatives.
All those adaptations have allowed sheardogs to drive to extinction archaic biwolves, becoming the dominant mesocarnivores.
Several species have successfully adapted to live in grasslands and prairies, like the lone sheardog (Gnathocyon savanicus), one of the largest biwolves ever.
As the name suggests, it's a solitary hunter that feeds on anything, from invertebrates to medium-sized ducktails. It's an extremely fast and tenacious runner that can maintain a constant speed of 40km/h (25 miles/h) for even an hour.
This sheardog becomes social only during the breeding season when temporary pairs live together to raise cubs. At the end of the summer, juveniles follow their mom while fathers return to their solitary life.
Despite their evolutionary success, sheardogs were not able to reach Marie Byrds, where it survives the last lineage of archaic biwolves. Thanks to their geographic isolation, this group of predators was able to survive as a relictual clade.
The most notable species is the cervino (Ancestricyon mariensis), which resembles an oversized lynx. Like them, it spends lots of time on the ground but it's also a decent climber. They are the only biwolves with grasping hands, which are used to hold their prey before being lethally killed with their powerful bite.
While not being as generalistic as sheardogs, Marie Byrd biwolves are still successful predators in their ecosystem: until another land bridge will connect their home to Polarica, they will continue to flourish in unique and spectacular forms.
However, the end of these insular carnivores will not be caused by new competitors but by something even more dangerous...
