You might have heard the expressions name dropping and jaw dropping but have you ever heard about arm dropping?

‘Arm dropping’ is the defence technique the banded string-arm-octopus uses to get away from predators.

Of course, the first defence for the octopus is to

• Hide in a crevice. Due to its soft body, it can squeeze into the smallest hiding spot.
• Camouflage or blending in with the environment is another method. The octopus can change its color in a split second.
• Squirting black ink to hide their getaway.
• And then there is ‘arm dropping’.

The octopus arm will wiggle around for up to 5 hours as if to say, ‘come eat me’.

Scientists have come across some string-armed octopuses managing just fine with only 2 arms. This species can regenerate their arms in as quickly as 6 to 8 weeks.

This kind of automutilation is well known in some octopus species. Animals with a missing or a regenerating much smaller arm are not uncommon. Of course it can also be due to the action of predators.

Remember from previous blog articles there are many different species that have this regeneration superpower. Starfish, mantas, sea squirts, flat worms and sharks.

Octopus arm with brains
Yes, the octopus’ arm has a brain. An octopus has 500 million neurons, more than half are found outside the brain. 60% of their brainpower are in each of their arms. These satellite brains communicate with each other without needing to report back to the central brain.

Sexy arm
There is something else special about the octopus’s arm and only the males have it. It can store sperm and come mating time the male will insert this arm into the female to deposit his sperm. He won’t just deposit the sperm, he will even break off his mating arm and give it to the female so she can fertilize her eggs.