Is the cuttlefish a mollusk?
Cuttlefish
Cuttlefish or cuttles are marine molluscs of the order Sepiida. They belong to the class Cephalopoda, which also includes squid, octopuses, and nautiluses. Cuttlefish have a unique internal shell, the cuttlebone.
Sexual mimicry
While, as seen before, most organisms which portray sexual mimicry are born with this morphology/behaviour, this is not always the case. The giant cuttlefish, "Sepia apama", mentioned above in the section “sneaky copulations”, is born with the capacity to choose whether to change its morphology to look like a female or a mature male. When no competition is seen nearby, the cuttlefish will look like a mature male and mate with the female. However, when a mature male and a female are copulating, the giant cuttlefish will resemble a female and stay at a close distance of the couple, hoping for a chance to mate with the female if the mature male leaves to fight other males. Another example of an organism that has the capability to remain small and look like a female, or become a morphologically mature male, is the dark-edged splitfin, "Girardinichthys multiradiatus". The purpose for their female mimicry was seen before, in the “sexual mimicry against aggression” section where the female-looking males will escape aggression from dominant males and avoid females fleeing their company due to persisting courting males.