Complex sentence: Octopus lifespan is limited by reproduction: males can live for only a few months after mating and females die shortly after their eggs hatch because they do not eat during the month spent caring for their unhatched eggs, and thus they die of starvation.
Split into simpler sentences: Octopus lifespan is limited by reproduction: males can live for only a few months after mating, and females die shortly after their eggs hatch. They do not eat during the month spent caring for their unhatched eggs, and they die of starvation.