Questions about the fly brain
Short answers to things people ask about flies and their brains. Each one comes with a lesson where you can see it for yourself.
How do flies smell?
A fly smells mainly with its two antennae. Smell receptors on them fire when an odor lands, and the signal travels into the brain to be sorted.
Do flies have memories?
Yes. A fruit fly can learn that a smell means food or danger and remember it for hours or days. The memory forms in the mushroom body.
How do flies know which way they are facing?
A fly keeps an internal compass: a ring of neurons where one patch of activity marks its heading. Turns move the patch, and landmarks hold it steady.
Why are flies so hard to swat?
A fly sees the swatter coming early, and a fast escape circuit launches it into the air in a few hundredths of a second, before the swatter lands.
How fast is a fly’s reaction time?
A fly’s fastest escape jump starts a few hundredths of a second after danger looms. A person needs about a quarter of a second just to react.
How many neurons does a fruit fly brain have?
About 140,000. In 2024 scientists finished mapping every one of them in one adult fruit fly’s brain, with more than 50 million synapses between them.