Q:

When does a fox have his time?

Rashi on Genesis 47:31 says:

וישתחו ישראל: תעלא בעידניה סגיד ליה:
and Israel prostrated himself: [Although the lion is king] when it is
  the time of the fox, bow down to him. — [from Meg. 16b]

What exactly does Rashi mean here?
I looked up the Gemara [Megilla 16b] , but there I only found that comparing Yosef to a fox is ok in comparison to Yaakov (as apposed to calling him a fox in comparison to his brothers)
This seems to imply that the fox is sometimes the greatest of animals (not sure where the lion part comes from as it doesn't appear in the Hebrew) and that is why (in the nimshal) even Yaakov bowed to Yosef.
My question is: Is this a known fact that the fox is sometimes greatest animal. If so - when?

A:

Mizrachi explains that even though a fox is considered the lowest of the animals, when you need it bow down to it, the same here, Yaakov bowed down to Yosef not because he was the King, only because he needed him and therefore bowed down to him.
Sifsei Chachomim says that there is a month when the fox is King.

A:

From the Prince by Machiavelli (I never thought I would reference Machiavelli on this site!)

A prince, therefore, being compelled knowingly to adopt the beast,
  ought to choose the fox and the lion; because the lion cannot defend
  himself against snares and the fox cannot defend himself against
  wolves. Therefore, it is necessary to be a fox to discover the snares
  and a lion to terrify the wolves. Those who rely simply on the lion do
  not understand what they are about.

From this it seems that there are times when the fox has his day.

