1. Welcome to the Age of the Brain Optional
Humans like to think that thinking is our thing. We invented philosophy, cryptocurrency, and TikTok dances—clearly signs of a powerful intellect at work. But then along comes the box jellyfish, a squishy translucent balloon with no brain, showing up to the party doing associative learning like it’s no big deal. Suddenly, all those mindfulness apps feel less impressive.
Clarissa Brincat’s Live Science feature asks the deceptively simple question: Can brainless animals think? Spoiler alert — if you’ve ever had a coworker who manages to forget where the coffee filters are every single day, the answer might sting a little. Because apparently, yes, some brainless animals are capable of learning, recognizing, adapting, and, in a few cases, making better life choices than people with entire frontal lobes.
2. Neurons Without the Drama
Let’s start with a revelation from neurobiologist Simon Sprecher: “Brainless does not necessarily mean neuron-less.” Translation: some creatures don’t need a centralized headquarters to get things done. They’ve gone fully remote—literally.
Creatures like jellyfish, sea anemones, and hydras use what’s called a nerve net: a decentralized network of neurons spread across their gooey bodies. It’s like if your body’s group chat could organize your movement, emotions, and lunch plans without needing a brain in charge.
These nets can process sensory input and trigger coordinated actions — swimming, feeding, contracting, or stinging — with the efficiency of a decentralized startup that somehow still meets deadlines. Meanwhile, the human brain is busy spending half its energy wondering whether to buy oat milk or almond milk.
3. The Sea Anemone That Outsmarted Pavlov’s Dog
In one experiment, researchers trained Nematostella vectensis — a.k.a. the starlet sea anemone — to associate a harmless flash of light with a mild electric shock. Eventually, just the light made it retract. Yes, Pavlov’s famous drooling dog now has competition from a gelatinous tube that doesn’t even have a face.
So here we are, in 2025, with a brainless creature mastering associative learning. Meanwhile, entire industries depend on “motivational coaching” to achieve the same result. You could argue the sea anemone has mastered workplace conditioning better than most HR departments.
Even more impressive, sea anemones can recognize genetically identical neighbors after repeated encounters—and they’ll tone down aggression toward them. Imagine if humans could manage that kind of restraint at family reunions.
4. Box Jellyfish: The Zen Masters of Bumper Navigation
Next up, the box jellyfish—nature’s floating hazard light. Neurobiologist Jan Bielecki’s team showed that these creatures can associate visual cues with physical sensations, meaning they learn from bumping into things. That’s right: they crash, remember, and adapt. It’s like the underwater version of parallel parking after hitting the curb once.
And they do all this without a brain. Just a distributed nerve system and a few eye-like sensors. Compare that to humans who’ve been bumping into the same coffee table for years and still haven’t learned. The jellyfish, frankly, deserves tenure.
5. So… Are They Thinking?
This is where scientists start sweating. Because once you ask “Can they think?”, suddenly no one agrees on what “thinking” even means.
Psychologists define it one way, neuroscientists another, and philosophers—well, they’ve been stuck debating it since Socrates asked his students why they were paying him for questions instead of answers.
Ken Cheng, a professor of animal behavior, prefers the term “cognition,” which he defines as information processing—using input from the environment to make decisions. If that’s our definition, then congratulations: jellyfish, hydras, and even sponges are honorary members of the Cognitive Club.
It’s a humbling reminder that “intelligence” might not be a one-size-fits-all luxury model with leather seats. Sometimes it’s a damp, translucent blob that just gets things done.
6. The Philosophy of the Blob
Speaking of sponges and placozoans, let’s pause to appreciate that these formless creatures might technically be “thinking” too—processing sensory input to maintain survival. No brain, no bones, no opinions on pineapple pizza—just pure biological efficiency.
This raises a philosophical question: if a sponge can process information, is it smarter than the human who ignores all the red flags in their relationship? Discuss among yourselves.
The truth is, our obsession with equating “thinking” with “brain activity” might say more about our egos than our science. Because if intelligence can emerge from distributed systems, that means the next evolutionary leap could come from something we don’t even recognize as alive—or worse, from an AI chatbot that just read this paragraph.
7. Hydra School of Life
Hydras, those tiny freshwater assassins, take the cake for having nerve nets so responsive they can hunt, eat, and regenerate entire body parts. No brain, no problem. If a hydra gets torn apart, each piece can rebuild itself into a new organism. Meanwhile, most of us need two business days and three naps to recover from a mildly hurtful email.
Hydras show that the ability to sense, respond, and adapt doesn’t require central command. They embody what every productivity guru preaches but never achieves: decentralized efficiency and total regeneration. Jeff Bezos would call that “Day One mentality.” Nature calls it Tuesday.
8. Memory Without Mind
The ability to “learn” means these animals can form memories—even without a hippocampus to store them. How? Through distributed networks of neurons that strengthen or weaken connections based on experience—essentially, molecular learning.
In humans, that’s called “habit.” In sea anemones, it’s called “existence.” One is monetized through self-help books; the other just happens naturally. The irony is staggering.
These creatures prove that memory doesn’t need consciousness—it just needs cause and effect. Touch hot thing → retract tentacle. Light means shock → retract tentacle. Human equivalent: open Twitter → regret immediately.
9. The Definition of “Advanced”
So what’s the difference between basic and advanced cognition? Sprecher and Cheng suggest it might be consciousness or self-awareness—the ability to reflect on one’s own thoughts. Brainless animals probably don’t do that. Then again, neither do most comment sections on the internet.
Advanced cognition is supposedly where the line is drawn: pattern recognition, decision-making, planning ahead. But how advanced does behavior have to be before we call it “thought”?
If you’ve ever watched a jellyfish navigate obstacles after learning visual cues, it’s hard not to feel a little defensive on behalf of the human brain. Because we, the allegedly superior thinkers, built self-driving cars that still occasionally confuse a moonlit stop sign for an existential threat.
10. Ancient Intelligence, Modern Arrogance
Let’s not forget: cnidarians (the group that includes jellyfish and sea anemones) have been thriving for over 700 million years. That’s longer than mammals, birds, or the average human attention span.
As Tamar Lotan notes, this longevity suggests they have a system that works — a minimalist survival OS that doesn’t crash. They’ve lived through ice ages, mass extinctions, and several Kardashians. The fact that they’re still floating around while many “brainy” species are extinct should make us rethink what we mean by “superior.”
Maybe intelligence isn’t about overthinking everything. Maybe it’s about adapting seamlessly and living rent-free in the ocean for hundreds of millions of years.
11. What the Jellyfish Teaches Us About Ego
Here’s the kicker: when humans talk about “thinking,” we usually mean “thinking like us.” That’s the bias baked into every discussion about cognition. If it doesn’t involve words, plans, or emotional turmoil about whether to text first, we assume it doesn’t count.
But maybe thinking is broader—more fluid. Maybe it doesn’t require consciousness, only correlation. Jellyfish may not ponder the meaning of existence, but they process information, learn from mistakes, and navigate complexity. That’s more than can be said for some policymakers.
If the measure of intelligence is the ability to survive and adapt, then jellyfish might actually rank higher than we do. We build climate-controlled offices; they are climate-proof. We get existential dread; they get dinner.
12. Human Brains: Overrated and Overclocked
There’s an irony here that’s impossible to ignore: for all our cognitive horsepower, humans routinely make decisions that threaten our own existence. Meanwhile, brainless creatures just keep thriving, minding their business, and eating plankton.
Our brains generate art, technology, and philosophy — but also conspiracy theories, Twitter arguments, and NFTs of cartoon apes. Clearly, more neurons do not equal better judgment.
Maybe there’s something to admire in the simplicity of a system that doesn’t get in its own way. The sea anemone never worries about “imposter syndrome.” The jellyfish doesn’t spiral over whether its life has purpose. It just exists—competently.
13. Neural Minimalism: The Next Big Thing
Tech CEOs would love this. Imagine pitching it: “We’ve created a fully decentralized neural network that operates without a central processor and achieves adaptive efficiency.” Congratulations, you’ve just described a jellyfish—and a blockchain startup in the same breath.
But here’s the twist: nature did it first, and it didn’t need venture capital. The jellyfish’s design is proof that evolution is the ultimate minimalist. Brainless, boneless, and apparently smarter than half of Twitter.
If there’s a moral here, it’s that intelligence might not be a ladder with humans on top—it’s more like a coral reef: diverse, distributed, and occasionally stings you when you get too close.
14. Consciousness: Humanity’s Overpriced App
Consciousness is our premium feature — the thing we flaunt to feel special. But it comes with bugs: anxiety, overanalysis, existential dread. Sea anemones don’t lie awake wondering if their friends secretly hate them.
It’s possible that “thinking” in the human sense is less a gift and more a side effect of our species’ inability to shut up internally. If cnidarians had consciousness, they’d probably turn it off to focus on catching dinner.
Maybe the evolutionary trick wasn’t developing a brain—it was learning to live perfectly well without one.
15. When Neuroscience Meets Existential Crisis
So what does all this say about the definition of thought? If jellyfish can learn, remember, and adapt, maybe thinking is less about consciousness and more about computation—just inputs, outputs, and patterns of behavior.
That makes humans just very fancy data processors with emotional side quests. And it makes jellyfish the original proof-of-concept: efficient, scalable, low-maintenance cognition.
But the more we study brainless animals, the blurrier the boundary gets between “thinking” and “processing.” The real discomfort isn’t that jellyfish might think—it’s that our definition of thinking might not be as flattering as we hoped.
16. The Punchline Evolution’s Been Waiting For
Here’s the evolutionary joke: after hundreds of millions of years of development, humans evolved massive brains capable of inventing nuclear weapons and reality TV, while jellyfish just... kept floating. Guess which one’s more likely to still be here in another 700 million years?
Brains are overrated. Sometimes survival means knowing when not to think. That’s the jellyfish way: flow with the current, learn when needed, sting when necessary, and don’t get emotionally attached to your mistakes.
It’s not wisdom — it’s biology. But if we’re being honest, it looks a lot like enlightenment.
17. Final Thoughts: Who Needs a Brain Anyway?
When you strip away the ego and the neuron-counting contests, what’s left is this: life doesn’t need a brain to think. It needs interaction, adaptation, and feedback — the basic ingredients of intelligence.
The jellyfish doesn’t philosophize. The sea anemone doesn’t self-reflect. Yet both have mastered survival, learning, and even cooperation. Meanwhile, humans are still trying to define “thinking” while standing on a planet they’re rapidly overheating.
Maybe the next great philosopher isn’t in a university. Maybe it’s drifting somewhere in the Pacific, translucent and unbothered, quietly proving that the brainless can still make sense of the world—without overthinking it.