ABSTRACTMost bacteria, including model organisms such asEscherichia coli,Bacillus subtilis, andCaulobacter crescentus, reproduce by binary fission. However, some bacteria belonging to various lineages, including antibiotic-producingStreptomycesand predatoryBdellovibrio,proliferate by nonbinary fission, wherein three or more chromosome copies are synthesized and the resulting multinucleoid filamentous cell subdivides into progeny cells. Here, we demonstrate for the first time that the predatory bacteriumBdellovibrio bacteriovorusreproduces through both binary and nonbinary fission inside different prey bacteria. Switching between the two modes correlates with the prey size. In relatively small prey cells,B. bacteriovorusundergoes binary fission; the FtsZ ring assembles in the midcell, and the mother cell splits into two daughter cells. In larger prey cells,B. bacteriovorusswitches to nonbinary fission and creates multiple asynchronously assembled FtsZ rings to produce three or more daughter cells. Completion of bacterial cell cycle critically depends on precise spatiotemporal coordination of chromosome replication with other cell cycle events, including cell division. We show thatB. bacteriovorusalways initiates chromosome replication at the invasive pole of the cell, but the spatiotemporal choreography of subsequent steps depends on the fission mode and/or the number of progeny cells. In nonbinary dividing filaments producing five or more progeny cells, the last round(s) of replication may also be initiated at the noninvasive pole. Altogether, we find thatB. bacteriovorusreproduces through bimodal fission and that extracellular factors, such as the prey size, can shape replication choreography, providing new insights about bacterial life cycles.