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document updated 8 years ago, on Jan 10, 2016
In the wild, rats usually dig multi-room burrows to live in. [1] [2]

If taken outside for a period of time, domestic rats will dig the same kind of holes. [2]

So, the question arises — can rats dig tunnels inside, in something akin to an ant farm? Yes, yes they can. [3] [4] [5] [6]