The largest octopus on Earth lives only three to five years, then dies right after mating

The giant Pacific octopus can grow arm-span over four metres and weigh as much as 50 kilograms, yet it lives a strikingly short life for its size: three to five years at most. Like most octopus species, it is semelparous, meaning it reproduces exactly once. A female lays tens of thousands of eggs, guards them without eating for months until they hatch, and then dies shortly afterward, her body already deteriorating by the time her young are born.

— Jennifer A. Mather, Roland C. Anderson and James B. Wood, Octopus: The Ocean's Intelligent Invertebrate — Timber Press, 2010
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