Figure 1. Flow chart of all nonrandom within-animal sequences of acts and postures for resident male rats when confronted with an intruder rat. Transitions from one act or posture to another are shown as straight arrows, and nonrandom repetitions of the same one are shown as reflexive arrows. The transition from anogenital sniffing to mounting occurred primarily in intruder rats, but is included here for comparison purposes. Abbreviations: (SGrA) self-grooming of anogenital area; (SGrS) self-grooming of the side; (SGrF) self-grooming of the face; (SAP) stretched-attention posture; (Expl) exploratory locomotion; (SnfN) sniff nose of opponent; (SnfB) sniff back of opponent; (SnfA) sniff anogenital area of opponent; (SnfT) sniff tail of opponent; (CrlU) crawl under opponent; (SnfD) sniff petri dish encrusted with scent marking; (COD) crawl over petri dish; (OSP) offensive sideways posture; (Box) boxing; (UP) upright posture; (FAP) full aggressive posture; (B + k) bite-and-kick attack; (AGrm) allogrooming; (Mont) mounting. Figure is redrawn from Lehman and Adams [1977] .