Most people think of fish as somehow lesser than pigs, cows, chickens and other land animals.
We have a vague notion that fish aren’t as intelligent (think of the common belief that fish only have a three-second memory) and genuinely wonder whether they can feel pain. Lots of people consider themselves vegetarians, but eat fish while abstaining from all other meats.
Australian biologist Culum Brown has a provocative argument in response, based on his years of research into fish behavior and learning. “They’re just not any less intelligent or sophisticated than terrestrial animals,” he says. “That idea is a total myth.”
Fish don’t have a three-second memory, Brown has found in fact, they can be taught how to evade a trap and remember it a year later. Fish can learn from each other, recognize other fish they’ve spent time with previously, know their place within fish social hierarchies, and remember complex spatial maps of their surroundings. There’s even some evidence, Brown has written, that they use tools.
So why do we think of fish as stupid? “People just don’t interact with fishes in any meaningful way,” Brown says. “The aquatic world is completely different from the terrestrial one, and fundamentally, if you haven’t seen an animal work in its environment and understand how it works, you’re really never going to fully understand it.”
All this, if true, could have huge ethical implications for the commercial fishing industry and, even more so, the people who consider themselves vegetarian but eat fish. Recently, Brown laid out this case in the article Fish intelligence, sentience and ethics. I spoke with him to hear more about his views.
Joseph Stromberg: First off, can you talk a bit about some of the fish capabilities that you’ve observed in experiments that might surprise people?
Culum Brown: The first one is memory. Everyone thinks that fish have a three-second memory. I have no idea where that started.
One of the first experiments I ever did with fish involved memory. I just caught some fish out of creeks around the university, put them in this fish tank, and ran an artificial trawl which is basically a net with a hole in it up and down the tank. To avoid getting trapped, the fish just had to figure out where the escape route was.
Within five trials, of roughly 15 minutes each, they had learned the escape route they knew exactly where it was. I thought that was evidence of rapid learning, but not all that surprising. But what did surprise me is that I tested them a year later, and they continued to improve their escape route responses. It was almost like I just did ten trials in a row. And in the wild, these fishes typically only live one year, though you can keep them up to five years in captivity. So effectively they had an hour’s training, and they remembered it for their entire lifetime.
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