Are flies easier to swat if you move slowly?

Does approaching a fly slowly allow you to swat it more easily?
09 October 2017
Presented by Michael Wheeler


A house fly


Jon wanted to know whether approaching a fly slowly makes them easier to swat. With the help of animal vision specialist Kate Feller from Cambridge University, Michael Wheeler's been swotting up on swatting flies.

Fly SFX - nebulousflynn

In this episode

A house fly

00:00 - What's the best technique to swat a fly?

It's Question of the Week and we've been buzzing about this question from John..

What's the best technique to swat a fly?

Michael Wheeler’s been buzzing about this question from John. So without winging an answer to this one ourselves, we put it to our listeners and Ian from Melbourne, Australia has discovered that confusing the fly with a clap of the hands makes the job easier. But what does our expert think - here is animal visual specialist, Kate Feller, from the University of Cambridge…

Kate - After discussing this question with several researchers at an animal vision conference in Finland, literally as naked scientists in the sauna, we all agree. Yes, this is possible.

Because fly motion vision is processed very fast, you can theoretically trick the fly by just moving very slowly. How fast the edges of your hand expand relative to the fly’s vision is what trigger is to flee, so a slow hand could confuse the fly. However, because the fly motion vision is so sensitive you would have to move so slowly that either you get bored and give up, or the fly just takes off. Because, you know, flies don’t stay in once place for very long.

Some alternative methods are to hold perfectly still and watch the fly until it starts washing itself, then strike quickly while it’s distracted, just like jumping him in the shower. You can also approach the fly at a normal speed and, instead of slapping it, clap your hand just above the fly to intercept it as it takes off.

Michael - The old “trap and clap” method. This one can even “be done on the fly”…

Kate - One other solution that a colleague recommended, and I have personally yet to try, is to spread your fingers wide on the same surface as the fly and pull your middle finger back like a slingshot while you slowly slide your hand towards the fly and quickly release the cocked finger once the bug is in range. Since the fly is being approached from multiple directions it should be confused enough to not take off as it normally to an approaching hand, so you can effectively squish it when you release your middle finger. I’ll definitely be experimenting with this method.

Michael - So, to any flies out there, beware the naked scientists.

Next week, We’ll be beaming out an answer to this question from Jayson:

Jayson - Our new house is 140 metres from a cellphone tower. As a family, the three of us feel like we have been affected to different degrees in terms of sleep, motivation, and anxiety, which are commonly reported symptoms of exposure to microwave radiation. It’s a controversial topic, but are there any major health risks with living close to a phone tower?



Thank you to Nebulousflynn for the fly sound effects. 


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