(image credit: by Pascal Ingelrest)
Squids are some of the ocean’s most intelligent creatures—but their anatomy might leave you scratching your head. With brains shaped like doughnuts and esophagi running through the middle, these marine marvels literally swallow food through their minds. Let’s dive deep into this fascinating feature.
A Brain Like No Other
When it comes to bizarre biology, squids reign supreme. While most animals have a clear separation between the brain and digestive system, squids are a little different. Their central brain is shaped like a ring, and right through the hole in that ring runs the esophagus—the tube that carries food from the mouth to the stomach.
This means that every time a squid eats, its food literally passes through its brain. That might sound risky (and it is), which is why squids can’t just swallow large chunks of prey. Doing so could compress the brain and potentially cause serious damage.
Instead, squids use their sharp beaks—resembling a parrot’s—to tear their food into small, manageable bits. Only then can the food safely travel through the neural doughnut.
Evolution’s Curious Design
So why would evolution design such a seemingly awkward system? Scientists believe it’s due to the cephalopod’s need for high-speed agility and coordination in the water. To keep their reaction times razor-sharp, their nervous system had to be extremely centralized and compact—so the brain formed a ring around one of the squid’s most vital internal highways.
Incredibly, this setup still allows for advanced intelligence. Squids show signs of problem-solving, camouflage mastery, communication, and even playfulness—traits rarely seen in invertebrates.
Their unusual brain also supports independent control over each arm, thanks to complex neural networks. In fact, much of a squid’s “thinking” happens not just in the head, but in its arms—each of which contains thousands of neurons acting almost like mini-brains!
More Than Just a Marine Oddity
This brain-through-the-esophagus feature makes squids a favorite topic for marine biologists and science lovers alike. It’s one of those facts that sounds like science fiction but is 100% real—and it showcases how creative evolution can be when designing creatures for life in the deep sea.
With over 300 species of squid roaming the world’s oceans, these creatures are as diverse as they are mysterious. Some squids grow to only a few centimeters long, while others, like the colossal squid, can reach sizes of over 40 feet—and yes, they all have that same peculiar brain setup.
Brilliant and Bizarre
From their camouflage skills to their donut-brains, squids are a perfect blend of brains, adaptability, and evolutionary weirdness. They may seem alien, but their story is a reminder of how wondrous—and downright strange—life on Earth can be.
Next time you see a squid in a documentary or on a sushi plate, take a moment to appreciate just how wild and wonderful their biology really is.
