In the first few stanzas, the fox is presented as a gentle creature, warily finding its way through the snow. As a wild creature, the fox presents no immediate danger to anyone nor is it being hunted. The fox is not aggressive as illustrated in the following:
"Cold, delicately as the dark snow,
A fox's nose touches twig, leaf"
"Delicately" suggests a tenderness and the inverted simile suggests the fragility of the fox: it is as fragile and gentle as snow. The image is further emphasized by the words, "nose," "twig," and "leaf" -- these are all delicate objects. The nose is a sensitive organ and a twig and a leaf are vulnerable and can easily be damaged or broken.
"Two eyes serve a movement, that now
And again now, and now, and now
Sets neat prints into the snow
Between trees, and warily a lame
Shadow lags by stump and in hollow"
These lines further accentuate the mild character of the fox. It is timid and unsure, suggested by the repetition of "and now" which describes its tenuous movements forward. It is wary and feeble and hangs back, unsure of itself. All this is symbolic of the gentle nature of this creature.
"a body that is bold to come"
in line 16 indicates that the fox's body language suggests a desire to be less careful, less timid. The fox seeks to express itself and be defined.
The next few lines build the suspense as the fox comes ever closer and one can discern its finer details, which grow larger. The fox is:
"Coming about its own business" (line 20)
It is there for a purpose of its own. This suggests an almost invasive presence, intent on achieving a specific purpose. The erstwhile uncertainty has gradually faded.
"Till, with sudden sharp hot stink of fox
It enters the dark hole of the head."
The former gentle timidity of the fox explodes into a violent expression of its presence. Ted Hughes emphasizes this suddenness through the alliteration of the 's'. Its presence is pervasive. The fox has violently entered its lair (the dark hole) and has announced its presence by sending out its "sharp, hot stink." These images are in sharp contrast to the previous gentle terminology. The words suggest an intensely forceful presence.
Ted Hughes has brilliantly used the arrival of a metaphoric fox to symbolize the genesis of an idea, its gentle growth culminating in its sudden, almost violent, expression.