Squid Detaches its Arms as Defensive Mechanism
Emily Tripp
University of Rhode Island postdoctoral researcher, Stephanie Bush, has observed a new defensive strategy used by a small species of deep-sea squid.
Octopoteuthis deletron, found in the deep waters of the northeast Pacific Ocean, counter-attacks its predator and then leaves the tips of its arms attached to that predator as a distraction. Bush explains that when it “jettisons its arms” in self-defense, the bioluminescent tips continue to twitch and glow.
“If a predator is trying to attack them, they may dig the hooks on their arms into the predator’s skin. Then the squid jets away and leaves its arm tips stuck to the predator,” she said. ”The wriggling, bioluminescing arms might give the predator pause enough to allow the squid to get away.”
The squid are capable of growing their arms back. For this reason, Bush explains, “there is definitely an energy cost associated with this behavior, but the cost is less than being dead.”
You can read more about her findings and watch a video of a squid releasing its arms here: Deep-sea squid can ‘jettison its arms’ as defensive tactic.

Common squid from the Belgian continental shelf. Picture taken in the lab on board of the RV Belgica, of a live specimen to preserve colour and structure of chromophores. Photo credit: Hans Hillewaert.
Copyright © 2012 by Marine Science Today, a publication of OceanLines LLC.

