Intro to Sundaland and Australia

Sundaland, that mass of southeast Asian islands that have risen from the sea higher than they ever have before, didn't fare as poorly as its tropical location might suggest. Granted, its previous climate did it no favors, but the fact that it was surrounded by oceans, slowing down its rate of cooling, provided some relief. It also had a fare share of highlands whose organisms were at least vaguely familiar with low temperatures. In contrast, no continent did worse than Australia, save of course for the long-dead Europe. Trapped on their island continent, Australian life had nowhere to flee until the watery barrier between them and New Guinea receded enough, and the aridity of the landmass ensured that temperatures would drop fast. Even when New Guinea became an option, they had to wait until the path to Southeast Asia opened up, much too late for most. As a final blow, Southeast Asia was doing much better than Australia and was filled with competitors.

Now two million years later, Australia - which now includes New Guinea contiguously - and Sundaland are more unified in biogeoraphy than they ever have been. Many Sundalandian animals and plants have jumped across the Indonesian Strait, as the waterway between the two continents is now called, for it no longer obstructs most waves of colonization. The plant life in both is surprisingly local, most descended from lucky plants that had some tolerance for cold temperatures and that occurred in favorable locations. Osmanthus fragrans, the sweet osmanthus, is a pleasant-smelling olive-like shrub that has seen great diversification thanks to its previous wide distribution. Jasmines, previously living here or in nearby portions of Asia, are another fragrant olive-relative which has produced common tree, shrub, and vine species. A few trees and shrubs are eucalyptus, mostly from Indonesia and Papua New Guinea but rarely from Australia. The temperature here is as agreeable as it gets, transitioning from the chilly desert of mainland Australia and the stripe of tundra on mainland Asia to subtropical savannas, broadleaf forests, and even rainforests in the wettest areas.

Sundaland in particular is a melting pot for animals, containing invaders from South Asia and East Asia or even further, those lucky natives of the area, and the even luckier refugees from Australia. In the grassy swaths, various budgies can be found subsisting on the glut of seeds. The mammalian fauna is mostly donated from the Himalayas, though some fortunate locals such as civets have maintained their stay. The Himalayas supplied its gorals, marmots, and pikas, as well as the giants of the new era. These are descendants of those wild Bactrian camels who made it through only via the blessing of luck, not to mention their advantageous set of traits.

The focus here is the area of forest bordering the southernmost portion of the South China Sea, which, while shrunken, serves to "catch" some of the warm currents flowing offshore, providing warmth and rain for the forests. Freezing temperatures are common during winter, especially at night, but on the new world few places get warmer. The delineation between the rainforest and the rest of the forest is as usual hard to define but is made worse by the fact that most organisms have not had enough time to specialize for one or the other. In the years after the biomes began to settle, specialization was a short-lived novelty, not a path to success.

In the great trees, various animals can be seen living their lives. Here, an owlfly larva, invisible against the bark it camouflages against, makes itself known by quickly nabbing a small bug in front of it. There, a strange-looking heavy-billed bird called a barbet keeps an eye out for berries, perching with its zygodactyl feet. As for larger creatures, few denizens are as notable as the wombear.

Wombats fled the Australian killzone with much trouble even with their extremely slow metabolisms and diet of tough plant material, but of course no one made it out easily. Here, surrounded by new competitors on all sides, a lineage of wombats was forced out of its comfortable holes and into the trees. As the ecosystem recovered, the pressure rose, and their stumpy limbs grew monstrously. With few predators, their bodies grew, too. Now, they can be seen clambering through the trees, even encountering eucalyptus trees, which might have given them nostalgia could they only remember.

Wombats were already noted for looking bear-like, but wombears are close enough to be mistakable for one. Having been chased into their new homes so suddenly, wombears are not the best climbers. Their shoulders, inflexible from a past life of digging, required that their front legs grow extremely long to give them a maneuverable reach. For females it's worse: their backward-facing pouches, once useful for keeping dirt out, now make climbing risky when carrying young. Mothers will instead live on the ground, sleeping in shallow burrows, the only use for such things the species has left. Regardless, they are the largest  arboreal animals in the area, weighing up to 95 kg (210 lb), and do well with what they have.

Clinging to branches in a sort of bear hug, they roam the trees in search of leaves to eat, stripping them from twigs with their shearing teeth. Though its diet is richer than that of its ancestors, it still takes much work to derive nutrition from its tough food. They are quite comfortable on the ground, of course, and will spend a fair amount of time there, especially if they feel they are in danger. They can better use their claws and their armored backside gifted from their predecessors against predators while on the ground.

Contrasting with the wombears is a creature of a much more acrobatic sort, at home in the trees and on the ground equally. These are the leopard-dogs, apex predators of the Sundalandian forests.

Leopard-dogs are neither dogs nor leopards, but mustelids. Specifically, they are descended from the yellow-throated marten of the Tibetan plateau. Spared the fate of small carnivores via their ability to target a wide size range of prey and to eat plant matter when needed, and prepared for the cold that awaited them down from the highlands, they quickly spread to India and Sundaland and diversified into an arrangement of predators big and small.

Leopard-dogs live a hybrid life in the trees and on the ground, hidden in the shadows with their spotted coats. They are not often seen alone, however; instead, they will hunt almost exclusively with another leopard-dog, and when not hunting they do not often wander far from their partners. Leopard-dog pairs are usually siblings, more rarely a mated pair, but occasionally a random animal that has happened to prove helpful. These relationships vary widely in their longevity. Sometimes they will pair up for only a single hunt, other times they will stay until one of the partners dies. At any rate, leopard-dogs are rather unique for their use of cooperative hunting, for it is largely a lost art on the new Earth.

Even while hunting, leopard-dogs do not commit to the ground or the branches. Pairs will stalk silently and slowly in the trees when targeting a prey item, usually something bigger than either of them. Suddenly, the pair will start after the prey, often with one leaping in the trees and the other running on the forest floor. When the time is right, the partner on the floor will run the prey animal almost directly into a tree, and while it slows to turn away from the obstacle, the other will drop from the branches onto it. When chasing wombears in particular, both partners will go after the wombear while it is in the tree, a much easier kill than when it is on the ground.

Leopard-dogs, though accepting of their hunting partners while they are helpful, maintain independent territories that are guarded against intruders, not unlike their ancestor. Their reverse countershading, very unusual for an animal that prefers to stay hidden, may help them stand out to conspecifics to prevent them from getting too close. Also like their ancestor, fights may break out between males during mating season, which occurs once at the beginning of the wet season and again a couple months before its end. Pups are playful, practicing their life skills, but are acquiring something else just as useful: a choice of partners for their hunts as adults.