When it comes to unconventional octopus characteristics, the argonaut’s ‘shell’ is a good place to start. “Because it’s not produced in the same gland, it doesn’t have that evolutionary lineage to it, ...

This story appears in the July 2019 issue of National Geographic magazine. Lest you doubt the awesome power of the drive to procreate, consider what Mr. and Mrs. Argonaut (Argonauta argo) must go ...