Separation of Trash
Summary is lost, so here's a summary of the summary:
The basic idea was that yukkuris used smell to define their ownership of a easy place so they would try to home invade by rushing and smearing their stench on the doormat.
It didn't work at all since either the human outsmarted the yukkuri using extremely cheap and easy to replace doormats that they would throw away, or outright ignored the smell rule.
Either way the invading yukkuri would end up kicked out or killed.
Illustration: post #19544