Though intelligent, cephalopods — octoposes, squid, cuttlefish, and the like — are deeply different from mammals; their last common ancestor with humans was probably some sort of worm with eye spots that lived 750 million years ago. These oceanic beings are probably the closest we’re going to get to meeting intelligent aliens, and thus why cognitive scientists, philosophers, and other mind-centric people are so entranced by them.
With a new paper in the Journal of Neuroscience — recently highlighted by Anna Vlasits at Wired — the many-tentacled plot just took another twist. Taiwanese neuroscientists Tsung-Han Liu and Chuan-Chin Chiao gained new insight into how squid control the kaleidoscopic displays on their skin. The species in question was the oval squid; for posterity, here’s a video of these cute little color-changers in the waters surrounding Hawaii.
Chiao placed electrodes in different parts of the optic lobe in the squid’s brain. Surprisingly, stimulating different spots on the lobe yielded color changes in the same body part. Indeed, it may be that the optic lobe controls the muscles that squeeze or stretch the squid’s pigment cells, which produce all those color changes.
As Vlasits notes, those color shifts can happen independently of one another :
When Chiao stimulated in one spot, the squid’s mantle turned dark. Another spot, the mantle got thick, horizontal stripes. Another, the mantle got one thin vertical stripe … Each part of the body has its own patterns, so a squid can simultaneously have polka dot fins, dark tentacles, and a stripy mantle. It’s like the squid has an alphabet of patterns—14 by Chiao’s count—which repeat in a mosaic within the optic lobe. It’s like if your keyboard had hundreds of keys, but still only 26 letters.
That redundancy may explain how squid shift colors so fast. Chiao speculates that it’s what allows a squid to morph its colors so quickly, creating a new composition second by second. What these color changes communicate to other squid is a point for further research.
Therein lies the promise — and peril — of studying these sea creatures: Their brains are so vastly different than ours, you can’t really use a primate as the comparison set. You might not even want to focus on the brain itself: In octopuses, for instance, over half the neurons are distributed through the arms.