Actually it is a Salvator Monitor or water monitor, about second in size to a komodo. He is about 7+ feet (tail and all) and about 65+ lbs.
A Savannah actually would fair well in the desert as they are from the Savannah in Africa. We have had two of these and they are very docile as well, our first one you could let out in the yard and he would come back in and back in his cage when he had enough outside and wanted to eat.
He is a beast but "dog" tame, they are very docile if handled regularly, but you have to respect them - I have experienced his teeth by my mistake when he grabbed to much off a plate of food and I tried to take some back as he was going for the gulp down. I could not imagine what damage they could do if they were to attack I barely scraped a finger across his teeth and it was about a 1/4 deep an a couple inches gash...
He was just a pup when we got him: