Reply: Item #6546311 from URTH at LISTS.BEST.COM@INET01#
Re: the Library rats. I took them as another example of creatures being shaped by their unusual environment, the most striking example being the Man Apes of the Saltus Mine. The Man Apes are in an environment laced with mutagenic substances (radiation, toxic wastes, etc.) and they never get to see the sun. (Tabloid Layer of TBOTNS: just as UFO sightings are explained in the text as time travelling saucer ships doing historical research, and "how people mysteriously vanish and where they go" is strongly hinted at with the timewarping Botanical Gardens of Nessus, if one needs more time for evolutionary mutations ala Man Apes one can just have them living on Earth right now--Yetis, gnomes, Lovecraftian servitor races, etc.)
The Library rats are in an environment oozing with knowledge, some of it activated by touch. They make their home within the laboratory maze of the =only= library on the planet.
(There were also some large talking moths in the Gardens of the House Absolute [II, ch. 27]--but maybe they were only talking to each other as animals talk.)
=mantis=