Planet's Waters Have More Intellect Than we Gave Them Credit For

Think of intelligence in the animal world and you rarely think of fish. But there’s growing evidence to show that the various species living in the planet’s waters have greater intellects than we’ve given them credit for.

- Dr Helen Scales

Many people don’t think of fish as being intelligent. Fish brains are too small and they’re too distantly related to humans to be clever; they lack feelings; they can’t feel pain – at least that’s how they’ve been typecast. Their simple-minded reputation means that people still tend to treat fish differently from other animals, with far less concern for their welfare (just imagine if we slaughtered cows by drowning them in the sea).

In the past, many scientists overlooked fish intelligence and didn’t bother testing for it. Those that did often used experiments that weren’t relevant for these animals, with senses so different from our own. But the science of fish cognition is catching up, and new studies are showing that fish are much smarter than previously thought. Signs of higher intelligence among fish are not only forcing a rethink of their lives and the way we treat them, but also how brains and animal intelligence evolved.

THEY CAN LEARN

In the 1950s, US biologist Eugenie Clark first showed that sharks can be trained using food rewards, just like lots of other animals. More recently, researchers in the Bahamas taught captive lemon sharks to press a target with their snout in return for food (image of lemon shark on previous page). When sharks were kept with others that already knew what to do, they learned the task faster than when they were left to figure things out for themselves. This kind of social learning is another important aspect of animal intelligence. Other studies have shown that young lemon sharks prefer to hang out in gangs with other sharks they already know. It’s not yet known if they simply distinguish between familiar versus unfamiliar sharks, or if they recognise individuals.

THEY’RE SELF-AWARE