Lookdown Waterworm

Splitting from its descendant, some Periscope Waterworms inhabiting the frigid coasts of the Drake continent would exploit the miles of sea ice above their habitat, and adapt an unusual lifestyle to do so.

Lookdown Waterworms, also known as "Lookdowns", are ambush predators specialized for hunting beneath the ice sheet of Sagan 4’s northern hemisphere. Several adaptations have allowed the species to pursue this niche. The periscope has extended outwards, forming into a cephalofoil which gives the Lookdowns an expanded view of potential prey on all sides. As the Periscope Waterworm adapted to hunting prey above it, Lookdowns do the same thing while swimming upside down, as the seafloor is traded for floating sea ice. In this position, Lookdowns float close to the ice sheet, remaining motionless and neutrally buoyant.

Being ectotherms in a freezing environment, Lookdowns are very sluggish, often staying completely still for days on end. Once its prey gets close enough, it will attempt to capture it with a quick burst of energy. Prey ranges from small pelagic swimmers, to pseudobenthic ice crawlers, to juveniles of larger creatures.

As Lookdowns live in an environment where the seafloor may be miles deep, the ancestral oviparous tactic of laying eggs within the sand no longer works. Instead they are ovoviviparous, developing eggs within the female for around 100 days before hatching, after which the young are on their own. It takes nearly 6 years for a Lookdown to reach sexual maturity, and can live for up to 30 years.

Lookdowns are much less willing to interact with others of their own species than their partially social ancestors, owing to their harsh environment. If two Lookdowns meet, and are not interested in mating, they will usually ignore each other. If an adult encounters a juvenile, the juvenile will often become a meal.