This study replicates previous reports which show that allowing a female hamster to carry out an attack on a conspecific increases its aggressive arousal, i.e., transiently decreases the latency and increases the probability of an attack on a second trial. We now report that attack priming also occurs in male rats. Interpolating delays of 0, 10, 30, and 90 min between the first and second trials resulted in similar patterns of temporal changes in hamsters and rats. The differences in gender, housing condition, and other factors make the parallel in the time course of aggressive arousal in these two rodent species quite striking. The results rule out a simple model of exponential decay with a short time constant. Carrying out an attack sets in motion a complex set of internal events that affect subsequent aggressive behavior similarly in hamsters and rats.