The first computer "bug" was actually a real moth
Today, a "bug" means a glitch in your computer code. But the very first one was a real insect that got stuck inside a giant machine!
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Last updated: February 3, 2026 at 06:08 AMToday, a "bug" means a glitch in your computer code. But the very first one was a real insect that got stuck inside a giant machine!
When your favorite app crashes or a game freezes, we say there is a "bug" in the system. While we use this word for digital errors today, the most famous "first bug" was a literal, six-legged moth.
In 1947, a team of engineers at Harvard University was working on a giant computer called the Mark II. Suddenly, the machine stopped working correctly. They searched through the massive maze of wires and switches to find the problem. To their surprise, they found a real moth trapped in one of the mechanical parts (Relay #70)!
One of the pioneers of computing, Grace Hopper, was part of this team. They removed the moth with tweezers and taped it into their official logbook. Next to the moth, they wrote: "First actual case of bug being found." While the word "bug" had been used to describe technical problems before, this event made the term famous in the world of computers.
Because of this moth, the process of fixing errors in computers became known as "debugging." Every time a programmer fixes a mistake in their code today, they are technically following in the footsteps of those engineers who pulled a moth out of a giant machine 80 years ago.
The term "computer bug" became legendary when a real moth got stuck inside the Harvard Mark II computer in 1947. Engineers taped the insect into their notebook, and ever since then, we have used the word "bug" to describe any problem that stops a computer from working right.