Tambuck

The tambuck split from its ancestor, the tamjack, when some floating nests drifted further east into the waters surrounding the supercontinent. Unlike the tamjack, the tambuck does not drift far out to sea, instead living among tlukvaequabora mangrove-reefs which encircle Dixon. It is a somewhat better swimmer than its ancestor; its spikes are now mobile and can be pulled flat against its body as to not interfere with swimming. It is also a decent climber, with each of its three-toed feet bearing a semi-retractable, semi-opposable thumb, which allows it to wander among tlukvaequabora roots and logs that rise above the water's surface. As a tamjack, the tambuck is somewhat intelligent and has advanced instinctive nest-building capabilities.

The tambuck is named for its enlarged incisors, which it uses to bite through flora. They do not grow continuously, unlike a rodent's teeth, so their large size ensures that they last at least as long as the tambuck's natural lifespan. It primarily feeds on aquatic flora, but it may venture onto the beach to consume flora found there as well. Tambucks without nests will also travel to beaches in search of good wood for nest construction. Tambucks are naturally monogamous and generally live as small family groups consisting of a mated pair with young, though they are not territorial and will interact amicably with neighboring families.

Though the tambuck still constructs radial basket-like boat-nests, these are mostly immobile and set among the mangroves where they will not drift away. Instead of dispersal, the floating nest now serves a new purpose—protection of its young. The pouch was a vestige of their ancestry because tambucks are placental and their young outgrow it quickly, and it created an unnecessary limitation on their ability to feed and doomed a mother to either starvation or drowning her babies if her mate were to die. So, the tambuck completely forgoes the pouch and can leave its offspring behind in the nest while foraging for food. As the nest is floating, it isn't in constant contact with any surface from which parasites or small predators might crawl on board. The sun beating down onto the nest keeps it warm enough that the young babies won't be chilled to death before their mother returns and they can nurse. The pouch is not completely lost, but now serves to streamline a mother tambuck's underbelly by containing her teats, somewhat like a built-in bra. The pouch and enlarged mammary glands are only present during late pregnancy and while nursing, as is the case in many Terran mammals.

The tambuck reproduces more often than its ancestor, giving birth to 2-4 babies at a time every 1–2 years. Tambucks gestate for 6 months, take 3 years to reach full size, and, barring early death by disease or predation, they can live for up to 30 years.