The Paraglire and the Ailurat: 

Unintentional Mutualism in the Glirrel Genus

The Paraglire (Caderitherium levis) is the smallest of the glirrels, though still on the large side for a swattermouse, having miniaturized significantly to a mass of around 100 grams. It is basal to the rest of its genus, and its lifestyle is not altogether dissimilar from the hunting strategy of its ancestor, whose other descendants have branched into many different niches. Its smaller size has allowed it to take greater advantage of its parachute-like tail, a trait that only modestly slowed the fall of its larger predecessor. For the paraglire, though, it has become an integral component of its hunting toolkit. It hunts prey bigger than itself, attacking by ambush. Running at full speed, its goal is to push the larger animal off a branch and send it fatally crashing to the ground below - even if the paraglire ends up tumbling down with it. 

Instead of engaging its prey - in this case, an exceptionally large type of nutcracker downling called a Caryopsicisor (Caryopsicisor fortis) - in a midair struggle for control, it simply leaves it to its fate, drifting down gently on its massive plume of a tail, which may be twice the length of the rest of its body. The paraglire's tail curves up over the back so its legs point towards the ground, guaranteeing a graceful landing. It must work quickly to strip the carcass clean of the best cuts of meat; the forest floor has many scavengers that would be happy to steal a bite of the paraglire's kill - or perhaps to make a meal of the small swattermouse itself while it's out in the open. The biggest threat comes from Giant Bone-Crushing Ratweasels (Osteophagomys ferox), a species of twenty-kilo predators that call the underground world of these forests their home. Their burrow exits are always well-hidden with vegetation, so a pack of them could emerge from anywhere at any time. However, a different thief is on the prowl today. Unlike the nomadic paraglire, this larger glirrel holds a permanent territory, so it knows there aren't any ratweasel tunnels near the caryopsicisor's body. Full of confidence, an Ailurat (C. capiens) steps out of the undergrowth behind the busy paraglire, which is currently hard at work dislocating the downling's left leg. When it spots its larger cousin, the fuzzy-tailed killer darts up the tree it came from; a leg is more than enough to fill its belly, and it stands little chance in a fight. 

The ailurat, unlike O. ferox, is only an occasional kleptoparasite. Most of the time, it actively hunts in the lower levels of the tree branches, for its five-kilogram body is too clumsy to move efficiently through the dense canopy. Downling in tow, it retires to its nest a few meters off the ground. While the paraglire's incisors are flat and thin, built to scrape layers of flesh off bone, the ailurat has a pair of triangular front teeth that curve backward, allowing it to stab deep and hold onto squirming animals. It too normally seeks out prey of a greater size category than itself, and it too has to worry about larger carnivores stealing most of its kills. A few hundred grams of caryopsicisor meat will satisfy it for a while, but it will soon have to go after something more substantial, for it needs to build up a larder to feed on while raising its pups later this spring. A well-stocked nest will mean it won't have to spend time away hunting, so its young will never be left alone and vulnerable. As the ailurat peels away piecies of downling flesh, it weaves them into the nest structure, making sure to incorporate soft, absorbent sodstalk fibers it carried from a nearby meadow. This will help dry out the meat, preserving it for a little while longer before decay renders it inedible. 

The paraglire builds a smaller version of the same nest, though it can't risk the journey to gather sodstalk foliage, so it uses some of its own tail fur instead. Both these nests are temporary; by the time the pups are weaned, the adults will have unraveled their handiwork to access the food within. Once the nest is gone, their parental instincts will quickly fade, leaving the adolescent glirrels to fend for themselves. The ailurat will drive its children out of its territory, while the paraglire will simply move on. Its last gift to its children will be this hunting ground - a place it chose to raise its offspring because it knew an ailurat was nearby. Though the two species may occasionally be at odds, paraglires are generally safer in an ailurat's territory. They face many of the same dangers, and ailurats are big enough to drive away carnivores that paraglires are helpless against. For example, at least half a dozen young terror kiwis had to be chased from the area after they began waiting around the half-built ailurat nest in hopes of scoring a snack while the parents weren't paying attention. If these birds had stuck around, they might have picked off the entire paraglire litter after they left home, but now they'll eat neither species. Though they'll never know it, the two rats have made this northern Loxodian forest just a bit more livable for each other.