Rats are quadrupedal animals of the rodent family. They appear in both S.T.A.L.K.E.R.: Shadow of Chernobyl and S.T.A.L.K.E.R.: Clear Sky. Like the Crow, it is a non-hostile animal which does not serve any significant purpose. Sakharov also has a rat in his laboratory in Shadow of Chernobyl that runs in a hamster wheel continuously.