Red-Blue was not happy.  The first few hours in the new cage, with all 12 rats together (both male and female) had been very exciting, and of course the presence of the females especially so.  But there was not enough space, and not enough places to hide.  Well, not any places to hide, actually.  The males had started to squabble over dominance again now that the females were present.  Before, they had tunnels to crawl in, to get away from each other at least for a while.

Red-Blue had taken to one corner of the cage, with its back turned to all of the others, and scratching obsessively at one spot.  There wasn't much to notice about this spot, at first, but it did have a tiny dent in it, too small for the humans to see but just barely visible to a rat.  Red-Blue had no particular plan or idea in mind when it decided to start gnawing at this spot.  It was not fun, but it did keep it away from the overstimulation of too many other rats in too small of a space.  So far, it had made little impact on the hard polymer of the cage, but doing it was better than doing nothing, which was impossible with so many others, so close on all sides, irritable and irritated and irritating.  Green-Red tried to come up to him, perhaps to groom him or perhaps to bite; Red-Blue warned him off with bared teeth and a growl that was inaudible to humans, but clear to Green-Red.

They were driving each other crazy, and they were all filled with a nervous energy that they could not spend on anything healthy, so they spent it on fighting each other, or on repetitive behavior.  Life had already shown them radical changes several times; when they got on the spaceship, when the ship landed in Martian gravity, and now being dumped into a cage too small for them to get out of each others' way.  If Red-Blue had been the sort to have thoughts about future prospects,  he would have hoped for another change to come soon.