2019-05-09 16:04:00 UTC
I read this book in the early '70s, probably a library hardback, but maybe it was a Scholastic Book Club paperback. It was illustrated, and aimed at the juveniles.
We found out with short warning that the Sun was going to blow up, and began loading things onto space arks to leave. While searching for samples of Nature, we found--I think--a unicorn. The book may have had it some more common cryptozoological type; a species of ibex or something, and my mind, even younger than the target audience, could only conceive it as "unicorn." In any event, it was not magical, and played no role in the story besides a morale lift for the chapter.