Merlene develops a fondness for conversing with the humans and eventually the humans and the keracks get to learn much about each other's worlds and cultures. The humans also teach Merlene more about science and technology which would hopefully advance the kerack race. The human scientists also uncover mysteries about the energy source of the keracks, who secrete an internal pellet of uranium and moderate its decay with a boron-rich carapace to provide internal warmth. Whenever a kerack dies its pellet is taken to be stockpiled by the colony's queen. The scientists discover the tragic conclusion of the kerack life cycle almost too late to save Merlene; when a kerack colony accumulated a large enough stockpile the queen would instinctively arrange it in such a way as to trigger a nuclear explosion, blasting kerack spores off of the Kuiper belt object to colonize other objects in the belt.