Could I tame a bacteria to do a trick?

Answer

Dear Piotr,

Some animals are indeed very smart, and you can teach them tricks. The smartest animals (if we do not count humans) are, for example, chimpanzees, dolphins. Some birds (eg crows and ravens) are also among the smartest animals in the world.

As you say yourself, an animal does indeed need a brain to learn tricks. Because to learn a trick you have to be able to do many different things: understand when a command is given, know what to do, remember what reward is given, and so on. The simpler the animal, and the less brains, the more difficult it is for that animal to learn a trick. Experiments have been done to see if worms have a memory. Surprisingly, they can indeed remember very simple things. But that’s not enough to learn a trick. Unfortunately, a worm can never be trained.

You may have heard of a flea circus, where fleas used to perform tricks on miniscule circus equipment. But I’m afraid that was mostly trickery: if you tie a miniature cart behind a flea, she’ll walk around with it, but that doesn’t mean the flea understands what’s happening.

You should certainly not expect anything from bacteria. They’re not even animals: bacteria have their own “kingdom” as they say, alongside plants, animals and fungi. A bacterium can only do what is programmed into its DNA. So the only way to get a bacteria to do what you want is to manipulate its DNA. Some researchers have succeeded: by inserting a certain gene into a bacterium, they can cause the bacterium to start producing a medicine that humans can use! You can probably call that a ‘trick’, right?