Squids, Axons, and Action Potentials: Stories of Neurobiological Discovery - JZ Young, Kenneth Cole, and Squid Axons at the MBL

Fish gotta swim, birds gotta fly, and squids gotta jet away from predators rapidly. All cephalopods (squid, cuttlefish, octopus, etc.) are squishy, soft-bodied animals; basically swimming food to anything that can catch them. As an evolutionary consequence, all members of this class of animals evolved a number of remarkable defensive strategies. Their camouflaging abilities are some of the most intellectually and aesthetically captivating behaviors in the contemporary animal world. The ink defense of some species of squid is likewise famous and makes inglorious appearances in popular movies and television, such as Finding Nemo and Futurama. And most people know that when they need to, squid can jet through the water at remarkable speeds, by some estimates up to twenty miles per hour.

Squid jet away from predators by sucking water into their mantle (the main part of their body), and then squeezing the mantle while allowing the water to exit in only one direction. As defense mechanisms go it’s a good one, but it has to be executed quickly and powerfully, which is no small physiological task. In order to accomplish the task, members of the Loligo genus of squid have long cable-like motor neurons which run from a specialized nerve bundle, called a ganglion, to the muscles in their mantle. These motor neurons, called the squid giant axon, were discovered by John Zachary Young, and rather by accident. Young was a charismatic and eclectic researcher. And in the early 1930’s he was traveling to many different labs in the UK, throughout Europe, and in the US.