Acunga

It is the late Pangeacene now, 240 million years P.E., and the wide assortment of strange animal clades which appeared early in the era have gradually whittled down to a smaller number of highly successful survivors. The Pangeacene has seen the rise of several very competitive tribbethere lineages, including canitheres, tribbats, and molodonts such as the circuagodonts. Many other "experimental" forms from earlier periods have died off as these lineages come to dominate ecosystems, to the exclusion of other relatives. Many leave no descendants at all. But some carry on, against the odds. One such species is the acunga, a descendant of the pteroti, and one which has managed to become even weirder than its predecessor.

The acunga belongs to a new family of tribbetheres closer related to canitheres and tribbats than to molodonts, now called tribbirds. They are the only descendants of the pteroti, and are primarily arboreal animals, usually from five to thirty pounds, with a suite of bizarre adaptations. Their forearms are modified into pincers, with only two large claws which can be flexed together to grasp, and their snouts are tipped with toothless, tweezer-like beaks. No other tribbethere has such a snout, and it is from this - and its resulting avian-like profile - that the tribbirds gain their common name. Tribbirds use their beaks to pluck seeds, fruits, leaves, and insects, often from high above or within narrow spaces in tree bark or sometimes in soil. They now have no incisor teeth, small canines, and very well developed molars; unlike most birds, they still chew their food before swallowing.

The acunga is a cat-sized tribbird of up to 14 lbs, native to the equatorial rainforest, which feeds on wood-boring insect larvae, spending its life climbing upwards on the trunks of old forest trees. Its hands are specialized to probe into tree bark, the paired claws being very narrow at their distal edge. Unlike most animals, its greatest strength lies not in the closing of its hands, but opening them; once it has pushed its claws into a hole, it forcefully opens them within, expanding the gap. Then it digs in with its pick-axe-like beak, and skewers out the prey hidden down inside. With its outer toes on each side of the hind foot very mobile and able to extend backwards, it props itself up as it clings to the bark and forages, and it can grasp branches to roost during the night.

Acungas remain largely solitary animals, but have some increased social complexity from their precursor. Young are capable of social learning, emulating their mothers' own techniques to forage, which can differ from one individual to another. Males and females now maintain lasting pair bonds, sharing a territory and defending it from rivals, though only interacting infrequently; males recognize their own young, and with this ability, may now try to kill off young that they did not sire. Newborn young, born one at a time or in pairs, are reared for their first few weeks in a hollow tree lined with moss and hair plucked from the mother's own breast; they begin to leave the nest around 21 days of age and are largely independent by six months of age. Individuals of all ages communicate primarily with body language rather than vocalization, and here their large ears come into play; both sexes now sport large ears lined with numerous small, fuzzy fringed of cartilage. Their ears are highly mobile and can be raised, lowered, spread, folded, and angled all manner of ways to indicate different emotional states and intent. Males, with larger ears, can flush them brilliantly red during courtship or antagonistic encounters, and males also grow long tassels of white hair during the mating season which further increase their size. Females, pictured above, have smaller ears without tassels, and spread them only when alarmed. At rest the ears are folded inwards and held along the neck, becoming narrow and inconspicuous. Vocalizations are rare and shrill; shrieking alarm calls, and the peeping cries of young separated from their mothers, are largely all that may be heard.