The squid is insanely intelligent, but we could be making their brains smaller. Photo: Unsplash
The squid is one of the most intelligent creatures on the planet. Depending on your definition of what “intelligence” is, they might be smarter than us, because they’re not rapidly killing their own environment. We, on the other hand, are, and as we do that, we could be making squids dumber.
According to a new study that was recently presented at the Society for Environmental Biology conference in Florence, Italy, climate change — which, unless you’re someone who listens to a random guy on YouTube instead of the vast majority of the world’s scientists, is definitely happening — is making the brains of squids smaller. Not climate change as a whole, exactly, but the increasing levels of C02 in our atmosphere.
The squid is crazy smart. There are 375 different squid species, and they can figure out mazes. They hunt together, using cooperative techniques, they can recognize different people and animals, and learn from their mistakes. If we’re counting neurons, they’ve got about the same number as dogs do.
We’ve known for a while now that higher levels of C02 affects squids. A paper published in January of 2026 proved that “seven days of exposure to increased carbon dioxide resulted in a 65 percent reduction in hunting behavior in adult squid, and that “newly hatched squid exposed to high CO2 for the first 90 days of their lives hunted 42 percent less.
In order to figure out why that might be, a couple of researchers, one from Acadia University in Nova Scotia and another from the Academia Sinica’s Institute of Cellular and Organismic Biology in Taiwan, took a few freshly-out-of-the-box big fin reef squids, put them in different water tanks, and mucked around with the C02 levels. One tank matched the ocean’s current carbon dioxide levels and the other used the levels predicted for 2100.
After three months, the poor squids were pulled from the tanks and killed so we could look at their brains. God, we’re terrible, but it was all in service of the health of the wider squid population. Their brains were scanned using magnetic resonance imaging, and the results were telling, to say the least.
“The brain volume of the squid in the elevated-carbon dioxide tank was 49 percent smaller than that of the group in the tank with current CO2 levels,” Time magazine wrote. “No area of the brain was spared from the shrinkage, but the change was especially pronounced in the optic lobes and the optic tract — the bundles of nerves that carry visual signals to the brain — with reductions of 52 percent and 62 percent respectively.”
Since the oceans absorb somewhere around 30 percent of the carbon dioxide in the atmosphere, the more we pump out, the more C02 the oceans are sucking up. That’s why ocean acidity is skyrocketing, which is, to put it simply, very bad.
“Like a sponge, our oceans are absorbing increasing amounts of carbon dioxide from the atmosphere,” the National Oceanic and Atmospheric Administration explained. “This exchange helps regulate the planet’s atmospheric carbon dioxide concentrations, but comes at a cost for the oceans and sea life, particularly shellfish such as commercially valuable oysters and clams. Ocean acidification is best known for its osteoporosis-like effects on shellfish, which makes building and maintaining shells difficult for these creatures. Acidification also affects other species vital to the marine ecosystem, including reef-building corals and pteropods (tiny snails eaten by numerous species such as fish and whales).”
If we continue to spew out insane levels of C02, it’s likely that entire populations of squid will suffer the same consequences as the squids in the test tank. It’s yet another sad reminder that we’re on a road to hell, and we’re not doing nearly enough about it.
