But as the grendels' numbers fall, their individual strength rises, as every dead grendel is food for the rest. Eventually, all that remain are the strongest and fastest fully grown grendels, and the colonists make a planned retreat to Weyland's mountain retreat. As the horde approaches, the colonists spray them with more supercharger, sending them into a frenzy once more. When they begin climbing the bluff, Weyland sets off a deadfall trap, killing even more. The grendels, though not as smart as humans, are smart enough to learn, given time and much experience. Their behavior changes as they realize the remaining colonists are not worth dying to reach when there are other grendels to kill. The colony is saved.