Placozoans are essential reference species for understanding the origins and evolution ofanimal organization. However, little is known about their life strategies in natural habitats.Here, by maintaining long-term culturing for four species of Trichoplax and Hoilungia,weextend our knowledge about feeding and reproductive adaptations relevant to the diversityof life forms and immune mechanisms. Three modes of population dynamics dependedupon feeding sources, including induction of social behaviors, morphogenesis, andreproductive strategies. In addition to fission, representatives of all species produced“swarmers”(a separate vegetative reproduction stage), which could also be formed fromthe lower epithelium with greater cell-type diversity. We monitored the formation ofspecialized spheroid structures from the upper cell layer in aging culture. These“spheres”could be transformed into juvenile animals under favorable conditions. Wehypothesize that spheroid structures represent a component of the innate immunedefense response with the involvement of fiber cells. Finally, we showed thatregeneration could be a part of the adaptive reproductive strategies in placozoans anda unique experimental model for regenerative biology.