Abstract: | Genetically sterile male Norway rats, Rattus norvegicus, were tested in the laboratory to determine both 1) behavioral characteristics, and 2) the ability of sterile males to compete aggressively and sexually with wild Norway rat males. Sterile males were larger in weight, more frequently dominant, won as many fighting encounters, were as aggressive as wild males, and mounted females more frequently. Behavioral activities were similar for both strains when compared under laboratory conditions with no apparent abnormal behavior exhibited by the sterile males. Use of sterile males in biological control programs is discussed. |