First, the scientists used high-speed cameras to film cockroaches running through narrow slits. They found the insects could slip through cracks about one-eighth of an inch (3 millimeters) wide — the height of two stacked pennies, and only one-quarter of the standing height of the roaches.
"Cockroaches are incredibly good at getting through small spaces, so we always had to keep an eye on them to make sure they didn't escape from our experiments," Full said.