Enriched environment (EE) is a key experimental paradigm, which has been widely used for studying the interactions of animals to the environment and differences to the controlled subjects. While many aspects of the influence of EE have been reported at the behavioral level, little is known about EE-induced hysteretic alterations in neural activity. We studied the acute changes in mice which had experienced an EE exposure for 30 min. Compared to control animals under standard conditions, we found increases in the event frequency of sharp wave-ripples (SWRs) in the hippocampus and the amplitude and duration of SWRs. We discovered that EE altered the event distribution of SWRs so that SWRs occurred in a series of clusters. These findings highlight the beneficial effects of EE on memory consolidation and provide insights into the relationship between the richness of the environment and the replay of memories in the hippocampus. Further research is needed to examine the detailed mechanism of EE-derived acute alterations by some types of behavioral tests.