" It was a monumental achievement that the serpentine tc'a had once upon a time gotten the knnn to understand the concept of trade: so nowadays knnn simply contacted a station, rushed onto its methane-dock and deposited whatever they liked, grabbed whatever they wanted and left. This was an improvement over their former behavior, in which they simply looted and left. "

― C.J. Cherryh , The Kif Strike Back (Chanur, #3)