7. They do not produce ink.
Producing ink is one of the special abilities many octopuses have, enabling them to escape from predators. Dumbo octopuses, however, like other deep-sea octopuses, have no ink sacs. This makes sense as ink wouldn’t serve any purpose in the dark.
Instead of ink sacs, dumbo octopuses have cirri or strand-like structures on their suckers which help them sense their environment and also help them find food, though their function is yet to be fully understood.