Adults live in the intestine of homeotherms. Birds and mammals from aquatic and terrestrial habitats are typical definitive hosts of the many species in this genus. Gravid proglottids are shed and pass in the feces. Arthropod intermediate hosts eat eggs that have been liberated from decaying proglottids, or may eat the whole proglottid. The eggs hatch in its gut and oncospheres use their hooks to penetrate into the body cavity. There the parasite develops into a cysticercoid in a few weeks. Ingestion by a suitable definitive host completes the life cycle.
Some species affect the behavior of their intermediate host in ways that may render them more susceptible to predation by definitive hosts. Many aquatic species produce eggs with external filaments that entangle in vegetation or aid buoyancy, to enhance predation by intermediate hosts.