The normal rectal temperature of a hummingbird is 104.6.
The normal rectal temperature of a bumblebee is calculated to be 110.8, although so far no one has succeeded in taking the rectal temperature of a bumblebee. That doesn’t mean that it can’t or won’t be done. Scientific research marches on; perhaps at this moment, bee proctologists at Du Pont…
As for the oyster, its rectal temperature has never been estimated, although we must suspect that the tissue heat of the sedentary bivalve is as far below good old 98.6 as that of the busy bee is above. Nonetheless, the oyster, could it fancy, should fancy its excremental equipment a hot item, for what other amongst Creation’s crapping creatures can convert its bodily wastes into treasure?
There is a metaphor here, however strained. The author is attempting to draw a shaky parallel between the manner in which the oyster, when beset by impurities or disease, coats the offending matter with its secretions, thereby producing a pearl, a parallel between the eliminatory ingenuity of the oyster and the manner in which Sissy Hankshaw, adorned with thumbs that many might consider morbid, coated the offending digits with glory, thereby perpetuating a vision that the author finds smooth and lustrous.
Even cowgirls get the blues, Tom Robbins, chapter 3.