The colonists are confounded by the ecology of the island, as there does not seem to be a sufficient food source for the creatures to inhabit it. An autopsy reveals that grendels (as the creatures are now known, in reference to "Beowulf") are crocodilian in appearance and behavior, with powerful jaws and claws, and a sense of smell better than a dog's. Its brain shows it is at least as intelligent as a gorilla. It possesses a snorkel enabling it to lurk under several feet of water. Its cardiovascular system and musculature give it strength and stamina far beyond that of humans. A grendel can release a super-oxygenated blood supplement into its blood that does to it what nitrous oxide does to internal combustion engines – enable short bursts of speed in excess of 100 miles per hour. This trait makes the grendels devastating, but is also the key to their destruction. Using the supercharger causes the grendels to heat up so rapidly that they die if they do not immediately return to water to cool off. With this knowledge and their technology and tactics, the colonists are able to wipe out the grendel population of the island within several months, making Weyland a hero to the people who previously turned on him.