Abstract We provide an anecdote of daytime activity within the northern giant mouse lemur (Mirza zaza), a small threatened primate that has always been considered strictly nocturnal, in the Anabohazo forest of northwestern Madagascar. During the dry season, we witnessed two individual M. zaza travelling separately in the afternoon period of three different days. Our observations indicate that M. zaza may undertake activity that is essential for their survival within both the light and dark periods of a day-cycle, and our findings suggest that the activity cycle of this species may be highly flexible. These observations have important implications to understand the evolution of activity patterns in M. zaza, and these findings warrant future, long term studies to establish the annual activity patterns of M. zaza and to determine whether this species is potentially cathemeral and why.