Our first clue was a frayed wire in D section, that Applebaum ran across while doing routine maintenance. It wasn’t frayed, of course, it was chewed, but we didn’t know that then.
Then we started finding droppings and tiny pieces of shredded paper in the crawlspaces. That was enough for the Cap to order a stem-to stern eyes-on.
The nest was in one of the engineering spaces. They were all through the food stores, too. This far out from Sol, with compromised food, we started to panic.
The doc suggested we get used to thinking of the rats as ‘livestock’.