kit fox (left) swift fox (right) exhibits

What species were here in the past? It's interesting to see that the zoo has Swift Foxes, Kit Foxes and Channel Island Foxes...not many zoos of the world (if any!) have that trio on display to the public.

One of these used to be fennec fox (which are now in another part of the zoo). They had them side-by-side with swift fox (I think) to compare similar species from opposite sides of the globe. Similarly, just before these exhibits, are side-by-side exhibits of bobcat and caracal to compare similar cat species from opposite sides of the globe.

As you mention, their collection of foxes (and carnivores in general) is truly impressive, which is why this zoo is among my five favorites. I love the cat collection (even with the sad move of black footed cat and sand cat behind the scenes). But just look at their collection of dogs and hyenas:
fennec fox
swift fox
kit fox
channel island fox
bat eared fox
african wild dog
mexican wolf
striped hyena

@Arizona Docent That is indeed an incredible list and I'm not sure how many zoos in North America can top that. I really need to make my way back to Living Desert Zoo at some point in my life as my only visit was in 2011. How time flies!

You would certainly enjoy a return visit, however best to wait a few years. According to a keeper I spoke with, the black rhino exhibit is slated for 3-4 years and the adjacent lion exhibit is slated for 5-6 years. Before that I spoke with a docent who claimed both exhibits would open in one year (even though construction has not started)! When I pressed him he said "we build things pretty fast" (this in spite of the fact that the nearly complete Australian Adventure is one year behind scheduled opening). I trust the keeper's estimate more than the docent's!