I have two theories about that. The first is that mutant aggression may be caused by the intrusion of several people into their territory, in which case that is normal behavior for most unmutated species, including humans. The other theory is that mutants are somehow capable of receiving the active emissions of our measurement devices. Clearly, the latter theory is far more intriguing.Ozersky
Hypothesis is a side mission available in S.T.A.L.K.E.R.: Call of Pripyat.
This mission is available from Ozersky after Anomaly research was completed. After Degtyarev reports that he and the team he was covering was under constant attack from mutants while the team was studying the anomalies, Ozersky tells him he believes that either mutants have a territorial behavior, or can react to emissions. In order to verify the hypothesis, Ozersky asks the player to use a special mutant detector in the Bitumen Anomaly and see the reaction.
Once the player is at the Bitumen Anomaly, they must plant the detector in the center of the area. After it is done, around ten snorks will jump into the anomaly. The experiment will end once all snorks are killed or after some time, so if the player isn't up to wait for the experiment to finish by itself, they will have to deal with all the snorks. This can be easily done by luring the snorks in the Vortexes which will be an instant kill. If the player does this however, a suit with good protection is required as the ambient heat will damage the player.
After the experiment is done, the player must collect back the mutant detector and take it back to Ozersky to complete the mission.
The reward for this mission is 3000 RU.