Marin looked. The evidence did indicate mice.
Before he could speak, the quartermaster snapped, "Don't tell me they're only mice-like creatures. I know that. The question is: how can I get rid of them?"
"Have you tried poison?"
"Tell me what poison to use and I'll use it."
It wasn't the easiest question to answer. What was poisonous to an animal he had never seen and knew nothing about? According to Biological Survey, the animal didn't exist.
It was unexpectedly serious. The colony could live off the land, and was expected to. But another group of colonists was due in three years. The colony was supposed to accumulate a surplus of food to feed the increased numbers. If they couldn't store the food they grew any better than the concentrates, that surplus was going to be scanty.
Marin went over the warehouse thoroughly. It was the usual early construction on a colonial world. Not esthetic, it was sturdy enough. Fused dirt floor, reinforced foot-thick walls, a ceiling slab of the same. The whole was bound together with a molecular cement that made it practically airtight. It had no windows; there were two doors. Certainly it should keep out rodents.
A closer examination revealed an unexpected flaw. The floor was as hard as glass; no animal could gnaw through it, but, like glass, it was also brittle. The crew that had built the warehouse had evidently been in such a hurry to get back to Earth that they hadn't been as careful as they should have been, for here and there the floor was thin. Somewhere under the heavy equipment piled on it, the floor had cracked. There a burrowing animal had means of entry.
Short of building another warehouse, it was too late to do anything about that. Mice-like animals were inside and had to be controlled where they were.
The biologist straightened up. "Catch me a few of them alive and I'll see what I can do."