The smell emitted by the plant is irritating for mice and they try to avoid them. Poo from bobcats, snakes, and cats are also effective mice deterrent because of their distinct smell. That smell scares mice away due to their natural fear on their predators. Pet stores have products that contain this unique smell which you can buy to spread over your house to keep mice away.
1) A myth exists that a cucumber smell comes from rattlesnakes. 2) The Tongue Mountain Range is known for harboring rattlesnakes. 3) The only place I have ever smelled random cucumber is the Tongue Mountain Range. Which leads me to believe the tiny minority, that rattlesnakes do in fact give off a cucumber smell.
Using Cucumbers. There are two locations of flavor in cucumbers, the skin and the seed mass. Sample an over-ripe cucumber and you'll find the slightly yellow seed mass to have a stronger and quite distinctly cucumber flavor. Personally I don't mind that flavor, in moderation, but some people don't like it.