Source: Incident at Absalom Station, pg(s). 58
It's believed that garaggakals can absorb and subsist on the planar energies of the Drift and only hunt for sport. They build lairs on the chunks of terrain floating in the Drift; these lairs are always temporary and only last until the garaggakal moves to better hunting grounds.
Garaggakals are intelligent and curious about other creatures. Garaggakals seem to divide all life into two categories: predators (themselves) and prey (everything else), making peaceful interaction nearly impossible. To a garaggakal, the best way to learn more about a new species is to kill, dissect, and eat it, not necessarily in that order.