Thanks Suzie for the pictures. They're extremely interesting.  I wouldn't have thought that a fox and cat could stand beside each , with such apparent unconcern.

The explanation might be this:

The fox was already quite well-fed.  You can see it has a thick abdomen. Indicative of a full, well-nourished body.

Whereas - suppose the fox had been "lean and hungry"!  Then wouldn't it have grabbed the cat,  bitten its neck, turned it over, ripped open the cat's bowels, and gulped down the visceral contents, don't you think?

Thanks again for your reply, best regards