My fert Loki yawns all the time, and even Koko does at times.  I don't
think it is anything to worry about unless it is accompanied by lethargy or
some other sign of disease.  I believe (course i'm not a vet!) that ferts
yawn for much the same reason we do:they don't have enough oxygen going to
their brains and a yawn helps stimulate that flow.  So don't worry about
it :)  Also, thought i'd share a cute fert story.  Yesterday I was playing
my viola and Koko decided she wanted to learn too.  She scaled my shoulder
and climbed out onto the strings where she proceeded to bite them and make
music!  It was sooo cute :) (note viola is very similar to a violin)
[Posted in FML issue 2616]