How small a hole can a mouse get through? Experiments.
Dec 8, 2017
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Experimenting with how small a home a mouse is able to fit through. But it didn't go as planned. I had a lazy mouse, and a hard working invading shrew.
http://woodgears.ca/farm/mouse_hole.html

Update: Two days later, the shrew squeezed itself through the 16.5 mm hole:
https://www.youtube.com/watch?v=ifCgW1Q_rto