I used to think dolphins were just really good at being cute.
Turns out, they’re also using sponges as tools—actual marine sponges, ripped from the seafloor—to protect their rostrums while they forage through sandy, rocky substrate in Shark Bay, Australia. This behavior, called “sponging,” was first documented in the 1980s, and researchers initially thought it was a solitary thing, maybe passed from mother to calf, a neat little party trick in the cetacean world. But here’s the thing: recent studies have shown that bottlenose dolphins don’t just sponge alone. They do it together, in coordinated groups, which changes everything we thought we knew about tool use in non-primate species. The dolphins in Shark Bay form what biologists call “sponger” communities, where individuals learn from each other, refine techniques, and even seem to prefer foraging alongside other spongers. It’s not just survival; it’s culture, passed down through social learning networks that rival, in some ways, what we see in chimpanzees or even early hominids.
Wait—maybe I’m getting ahead of myself. The mechanics matter here. When a dolphin hunts in sandy or gravelly areas, it’s probing for fish hiding beneath the surface, and that constant contact can damage the rostrum, which is packed with sensitive nerve endings. The sponge acts like a glove, or maybe more like a probe extension, letting the dolphin dig deeper without injury. Simple enough, right?
Why Cooperation Makes Sponging Even More Remarkable Than We Realized
Except it’s not simple at all, because cooperative sponging introduces layers of complexity that scientists are still untangling. In 2020, a team led by researchers at the University of Zurich published findings showing that spongers in Shark Bay spend significantly more time with other spongers than with non-spongers, even outside of foraging contexts. They’re not just working together—they’re hanging out, forming bonds, creating subcultures within the larger dolphin population. This isn’t accidental. The dolphins are actively choosing partners based on shared behavior, which suggests that tool use isn’t just a skill; it’s a social identity. I guess it makes sense when you think about it: if you’re going to spend hours every day doing something as specific and weird as wearing a sponge on your face, you’d probably want friends who get it.
Honestly, the implications are kind of exhausting to consider.
Cooperative foraging with tools implies a level of cognitive sophistication that we’ve historically reserved for humans and a handful of other species. Dolphins have to recognize that another individual is using a tool, understand that this tool confers an advantage, learn how to use it themselves, and then coordinate their efforts with others who are doing the same thing. That’s not instinct—that’s cultural transmission, and it requires memory, imitation, innovation, and social cohesion. Some researchers have even suggested that sponging might be linked to genetic factors, since it’s predominantly seen in female lineages, but the cooperative element complicates that hypothesis. If it were purely genetic, you wouldn’t expect to see such strong social clustering or the kind of behavioral variation observed between different sponger groups. Different pods seem to have slightly different techniques, different preferences for sponge types, different foraging rhythms. It’s messy, varied, and deeply social—exactly the kind of thing that makes studying dolphin cognition both thrilling and maddening.
The Uncomfortable Question of What Tool Use Actually Means for Animal Intelligence
Here’s where I start to feel uncertain, maybe even a little uncomfortable: if dolphins are capable of this, what else are they doing that we haven’t noticed yet? Tool use was supposed to be the line, the thing that separated us from them, and we’ve been moving that line for decades now—crows use sticks, octopuses carry coconut shells, sea otters crack open mollusks with rocks. But cooperative tool use, with cultural transmission and social learning? That’s rarer. That’s the kind of behavior that makes you reconsider the entire framework of animal cognition. I’ve seen footage of sponger dolphins working in tandem, moving through the water like synchronized swimmers, and it’s hard not to project intention, strategy, even joy onto what they’re doing. Maybe that’s anthropomorphism. Maybe it’s not. The research is still ongoing, and scientists are cautious—rightly so—about making grand claims. But the data keeps piling up, and it definately points in one direction: dolphins aren’t just smart. They’re cultured, cooperative, and using tools in ways that challenge every assumption we’ve made about what it means to be intelligent.
Anyway, I’m not sure where that leaves us, except humbled.
