Orange Yellow, former "lab rat" who was now just a "rat" that lived in the Recycling Rooms, was pregnant.  The question of whether or not she "knew" that she was pregnant, is an epistemologically fraught one.  What does it mean, exactly, to "know" something?  There are many times when we do, in some sense, know that an event is impending, and yet it surprises us, and so also in some sense we did not know or it would not have been surprising.  He was going to die soon.  She was going to leave you.  It was not going to work.  It would get better over time, and eventually not really hurt any more.  One would get better with practice, and what seemed hard to do now, would eventually be easy.  In all of these cases, even with someone as linguistically oriented as a human, some part of the brain knows, but other parts of the same brain do not know (at least not at first).

The primary difference for Orange Yellow, is that her species did not concern itself with labeling its own brain's contents, or expressing them in language.  Only that first part, the part of the brain that knows what is coming but cannot express it in words, existed in her little rat skull.  That she felt herself grow slightly heavier, and had an urge to make and remake and relocate her nest, and was always hungry, was in no way surprising to her.  Nonetheless, she had never done this before, and was uncertain and nervous.  That probably had something to do with her dissatisfaction with her first, second, and third choice of where and how to build her nest.

"Man," said Raymond, "she's moved her nest again.  Why does she keep doing that?  Is she bored?"

"Can rats get bored?" asked Mildred.

"Of course they can," said Dorothy, "they can be frightened and they can be happy so they must also be able to be bored."

"She doesn't look bored," said Stanley.  "She looks nervous, moving around in circles and fussing over everything."

Orange Yellow was nervous.  She was not exactly thinking anything like, "will my pups accidentally wrap this bit of thread around their neck and choke themselves to death while I'm not paying attention?  I wish I had wood chips instead of fabric, to make a nest with!"  But she was, effectively, doing something similar.  She would arrange the bedding material that had been provided for her by the New Soil Crew, sometimes chewing it into smaller pieces, rearrange it, and then pause and see if she felt calm about it.  She did not.  First time mothers are often uncertain about whether they are ready, whether they have adequately prepared.  When nervous, sometimes she would decide to move the entire nest to a different spot in the bins-connected-by-pipes contraption of a home that she had been put in.  Other times, she just went to eat more.

"She is eating too much, I think," said Eugene.  "She's getting fat."

"Leave her alone!" said Dorothy.  "She's just big-boned."

"She is getting bigger," said Raymond.  "Maybe she's not done growing yet."

"The trip from Earth was months long," said Stanley, "and they weren't babies when they left.  She should definitely be fully grown by now."

"But who knows how long rats take to grow up?" said Mildred.  "Maybe it takes longer than you think."

"Anyone knows, if they just look it up," said Stanley, looking at Mildred with one eyebrow raised, and an expression like he was wondering if something was wrong with her.

"Stench and leakage, Stanley, you take the fun out of everything!" said Mildred, with a light tone that indicated she was not actually upset.  She found it inexpressably fun to be around a real, live rat.  Chickens and honeybees were the only other animals she had ever seen live, in person, and rats (if they are clean, and well behaved, and not emerging unexpected from some corner of your house on Earth) are much cuter than either chickens or honeybees.

A human, if separated from all of their peers and companions, might pine for the lack of them.  Did Orange Yellow ever think about Red-Blue or Green-Red, the fathers of the litter she was carrying within her?  Did she ever think about the other females that she had shared living space with for months on the way to Mars?  Not exactly, not in the way that we might.  However, she did occasionally see them in her dreams, and she would have thrilled immediately if she had smelled or seen any of them.  Well, she would have before; pregnant rats are often a lot less welcoming of the company of other rats.

"Watch what happens when we put her harness on," said Raymond.

Orange Yellow saw the hands descending towards her, with the harness that had a camera and small lights attached.  She was familiar with it, and had come to associate it with getting food, so she paused and sat up, to get into the harness more quickly.

She had learned that if she turned towards whichever shoulder light flashed on, she would sometimes get a treat.  She was nearly always hungry now, so she was even more than usually motivated by this.  Even if the reward came only one time in three or less, it was still worth a try.  It helped that, each time the harness was put on, she did at some point get food.

"You can basically steer her, like a toy rover," said Raymond.

"That's mean!" said Dorothy.  "She's not a toy, she's a living being!"

"Yeah, a living being that's hungry," said Eugene.  "What's mean about giving her food and having her walk around?  It's not like it hurts her."

Dorothy frowned, uncertain as to exactly why she didn't like it, but certain that she didn't.  Finally, she realized what was bothering her.

"It's manipulative, it's degrading," she said.  "It's treating her like a piece of equipment."

"This is actually a lot better than most of the things that get done to lab rats," said Raymond, who had read quite a lot about how science used rodents to test its various theories.  "She gets a little exercise (which by the way she was probably going to be walking around anyway), and she gets fed.  Lab rats usually get a lot worse."

Dorothy scrunched her mouth sideways and experienced a moment of doubt.  She looked to Mildred, for confirmation and support.  Mildred shrugged.

"She doesn't look upset," said Mildred.

Indeed, Orange Yellow was not upset.  She did not find the harness to be uncomfortable, as it was not especially heavy, and she had learned not to try to chew it off since Raymond had made the wire one.  In fact, if she had known that the previous (cloth) versions of the harness would lead to getting fed more food, she would not have been so insistent on chewing them off.  It was not especially heavy, and the lights were not bright enough to be annoying.

It was, essentially, like playing a very simple game, in which there were very few rules (left light = turn left, right light = turn right, both lights = go forward, neither light = stay still).  Given that fact, she much preferred it to being crammed together with too many other rats in too small a space.  Although, she did occasionally dream that she was back with some of them, and felt happy when those dreams happened, so perhaps she could have used some company of her own kind.  However, in some not-exactly-knowing-but-not-exactly-not-knowing kind of way, she was aware that she would be getting more of her own kind soon, and having other adult rats around then, would have stressed her out.  Rats cannot always be trusted to treat rat pups kindly, especially if they are not their own.

"How far can the signal go?" asked Mildred.  "Can you steer her from across the room?"

"If the path is clear," said Raymond.  "Once she goes into the metal bins, though, sometimes the signal gets dodgy.  I'm working on using different frequencies, to make it more reliable."

"So, like, we could in theory race them, like we did the chickens?" asked Mildred, the smile on her face getting bigger.

"I don't think we should put the rat with the chickens," said Raymond quickly.

"No, silly, I mean a race with all rats," said Mildred.

"But we only have one rat," said Raymond.

"We only have one rat, so far," corrected Mildred, with a mischievous grin.  "There are more of them, roaming around, if they haven't been caught by the cat yet, and maybe we could catch some more.  It would be cool to have more rats."

If Orange Yellow could have understood what they were saying, she would have laughed.