Ploose

A shy but highly social diver from the polar basin, the elusive ploose spends almost all of its life swimming deep below the lake waters, rising its snout up only briefly to breathe. 

A large descendant of the platyporp, the ploose is a fully aquatic fish-eating predator which has been able to reach a length of up to five feet in the depths of the polar freshwater ocean, which it does not leave seasonally as do many endemic animals. It also doesn't leave the water, not even to rest, and again finds itself unable to walk for this habitat is large and expansive, and land is rarely in sight; this back and forth evolution of lifestyle, from sea to land and back again, demonstrates that evolution is nonlinear and lacks a goal, only serving to make species suited to whatever condition they find themselves living in, and that those conditions frequently change over time.

Though it is not an especially fast swimmer, the ploose can turn very quickly to outmaneuver larger enemies. Instead of chasing fish in open water, it usually forages at depths of up to 250 feet, stirring through the seabed with its very sensitive bill to collect small prey which hides either within the sand, or swims over its surface. The snout (except at its very tip) is not a hard beak as in some birds, but rather a smooth only lightly keratinized surface. It is densely with nerves and with a reflex to snap the pseudotooth-lined jaws closed over any movement, and also contains pits which detect electricity to detect fish moving nearby without vision. Sight has become a sense that is less needed, and so its eyes have reduced in size significantly.

Plooses have to deal with one trait which evolved to favor their survival in a very different past habitat; their young are born small and poorly-developed relative to other marine animals, a vestige of their evolutionary ancestry as much smaller semi-aquatic animals which could give birth on land. Newborn plooses, born in litters of two to five, are unable to swim on their own for as long as two weeks after birth and must be kept upon the back of an adult at the surface, though they do instinctively float if they fall off and so can be re-collected. They usually require the care of at least three adults to survive, in an example of obligate cooperative breeding: two must always attend them, one keeping them on its back above water and the other defending them from potential enemies, while the third collects food, but success is best with four or more adults to distribute duties with. The ploose thus lives in hierarchical social structures, with one dominant breeding pair and 1-4 helpers which are usually siblings or older offspring, but may be unrelated. Before any individual can have its own offspring, it will apprentice as a caretaker for another pair for as long as three years, learning valuable skills. Chicks are always born in the polar winter, when they are less visible to predators, and are kept in shallow, vegetated coastal waters where they are less vulnerable to aquatic hunters but still safe from land-dwelling ones. By two weeks the chicks can swim, and by a month they are capable of dives of several minutes, allowing the families to migrate back far out to sea where they otherwise make their homes.