"Red-Blue", the lab rat, was starting to feel better.  The first day after returning to gravity, had been extremely uncomfortable, for him and for his friend Green-Red and for all the other lab rats (a dozen in all, six in each of two enclosures).  But, just as they had adapted when the spaceship took off from Earth and gravity had disappeared, they adapted again when it came back (albeit to only a third its previous strength).  He still felt tired almost all the time, but his body was quick to adapt, and had for the last 24 hours been sending resources to build up muscle again.

You might have thought that it was more difficult to adapt to gravity going away, than having it come back, especially given that Red-Blue had no way of knowing why it had all happened.  However, as with all of his fellow lab-rats, Red-Blue did not spend too much energy trying to reason about the "why" of things.  This was not because its brain was smaller, although certainly that would have made highly abstract theorizing difficult, if not impossible.  Rather, it was because in the life of a rat (lab or otherwise), there was just not a lot to be gained from such theorizing.  Red-Blue knew, in a way that was too fundamental for it to even be aware that there was any other way to think, that it was going to have unexpected things happen throughout its life, and that no amount of thought ahead of time would change this.

There are personality differences between one lab rat and another, that make them either more or less optimistic, more or less curious, more or less adventurous.  Even for a given rat, their propensity to embrace change as opportunity, or flee from it as risk, could change from day to day based on how it feels.  But all of the rats in the spaceship's rat experiment knew that the world would do to them, and with them, whatever it wanted, and they would have to react and respond, never to be in firm control.  This was true when their recent ancestors were chosen for one experiment or another, it was true when their more distant ancestors played "games" of cat-and-mouse with larger predators while trying to avoid starvation, and it had been true when their even more distant ancestors had been scurrying about in hiding, amidst the footprints of dinosaurs.  Most of them, would not make it, not manage to live long enough to pass their genes on, but a few would, and those who did could succeed in numbers sufficient to keep the line alive.

Not that Red-Blue thought about any of this, either.

What Red-Blue thought about, was that the female human who brought food, was with a second female human this time.  It might come as a surprise to you to know that a lab rat could know, from the scent, if the human it was smelling was female or male, but it was not only something Red-Blue could do, it was something that came so easily that his little rat brain could not imagine how someone might not be able to know this.  The two humans that normally brought them food were one male, one female, and he knew this nearly immediately, the first time he smelled them.

But this time the second one was a second female human, new but somehow familiar.  Related?  In fact, Red-Blue realized as he twitched his nose and explored the new scent, the new human was a mix of the other two, the female and the male, along with some other unfamiliar scents.  "Their granddaughter" did not occur to him, since "granddaughter" was an abstraction that he had no use for, but nonetheless the fact that the new human was a mix of previously known (and unthreatening) scents, was reassuring.  The new human petted him, and he sniffed and licked her fingers.  She rubbed his belly, and he laughed.  Unknown to him, his laughter was far too high pitched to be heard by the humans.

"He likes it, I think," said Dorothy.

"I think so," said Sarah.  "He's a friendly one, maybe a little more than the others."

"He's cute!  Grandpa, come look!"

"I've seen him," said Jacob good-naturedly.  "He is cute.  I don't think they like me too much, though."

"You pet the cat too much," said Sarah.

"I wash my hands before I come into this room," said Jacob.

"I think they can still smell it," said Sarah.  "I never pet Loki until I've already fed the rats that day.  I think the smell of cat stresses them out."

"I doubt they can smell Loki after I've washed my hands," said Jacob.

"I can still smell him, so they probably can," said Sarah.  Jacob, upon hearing this, looked up from where he was doing some routine maintenance on the equipment that sterilized and purified the rats' water, and blinked, as if trying to decide if he believed what he was being told.  He sniffed his hands, with a look of skeptical concentration.  Sarah stepped over, gently grabbed his hands, and sniffed them herself.

"Yes," she said, "Loki, plus I think maybe you shook hands with Joshua, or else maybe clapped him on the back."

"You're making this up," said Jacob, half grinning.  "You just saw me clap him on the back."

"No, but Joshua is a pretty sweaty guy, so his scent is pretty easy to smell," said Sarah.

"Is he the one who is always joking?" asked Dorothy.

"If you want to call them jokes," said Jacob, more than half grinning.  "He's the one who drove us here from the Colony, and then drove the rover back."

Red-Blue and Green-Red were now chasing each other around their small enclosure.  Most of it was tunnels, to allow them to feel comfortable and move around even in very low gravity, but there were a few larger boxes that it connected to, and that allowed for more wrestling play.  Then, abruptly, they stopped, and sniffed the air and Sarah's hands as she removed and replaced the cloth that was put into their enclosure to use as bedding.

"They smell you, I guess," said Dorothy.

"They smell their lady friends, too, I think," said Sarah.  "Whenever I feed the females first, the boys get very curious about the scent."

"Let it go, lads," said Jacob, with a grin.  "Nothing but trouble that way."  Sarah's frown in response was, Dorothy thought, only somewhat good-humored.