Which animal has the most extended period of gestation for an invertebrate?

Octopuses have the longest gestation period among invertebrates, which can last from several months to over a year depending on the species. During this time, the female octopus carries and protects her eggs, which are laid in a den or crevice, until they hatch into tiny planktonic larvae.

The long gestation period is due to the relatively low temperatures of the deep sea, where many octopuses live, which slows down the metabolic processes necessary for embryo development. Additionally, the female octopus will not eat during this time, dedicating all her energy to caring for her eggs.

The giant Pacific octopus, for example, has a gestation period of around 5 months. The veined octopus, on the other hand, carries her eggs for up to 14 months before they hatch. This extended period allows the larvae to fully develop before entering the planktonic phase of their life cycle, which is crucial for their survival in the open ocean.