Possessing some social intelligence, Irridalli travel in loose pods to locate swarms of suitable food, at which time they separate and attempt to drive the prey nearer the surface, thus rendering them easier to capture. Despite this initial co-operation, the actual hunt itself is performed independently of the other pod members, cooperation only resuming when prey needs to be driven towards the surface once again.
While Irridalli are quite fast, many prey species are considerably faster and swimming speed is not their primary weapon: Moving in behind prey, the large eyes fix on a target and when in range two tentacles launch outwards as an elongated and lethally barbed lower jaw attempts to impale it. If the strike is successful, the tentacles rapidly coil around the doomed creature and draw it towards the mouth.
Like most apex predators, the Irridalli suffered major population depletion in the period leading up to, and during, the fall of birrin civilisation. As the birrin recovered, so too Irridalli populations increased in parts of their former ranges as prey species returned. The loss of genetic diversity however has resulted in higher than expected parasite loads in some pods.
Once hunted by the birrin as food, they are now rarely eaten both because they are widely protected, and are so infused with accumulated industrial poisons they are mildly toxic to ingest.
Industrialisation of Chriirah has had a dramatic effect on many of the planets’ ecosystems. The equatorial zone of this world, dominated by a vast superheated region named the Kiln, has seen perhaps the most extreme changes as the desert continues to expand.
Agricultural needs necessitated the damming of several major rivers to provide irrigation for Kiln border areas, and the lakes these rivers once fed began to evaporate. Ultimately most of these lakes vanished, leaving behind shallow sandy basins and ghost towns.
Unable to afford relocation, or unwilling to spare the expense, shipping companies left their craft to rust on the dry lakebeds.