There is a campaign mission, troubled zoo, where you have to satisfy all..

Put some tall grass or trees around so the animal will have more privacy. You can also give them a better covered shelter. The best thing to do in this situation is to replace some of the fencing with fencing that the guests can't see through. The socialness isn't always that the animal wants another animal, but they feel uncomfortable when guests are looking at them to much. I have had this problem many times before.

You don't have to put him with another camel, just another animal from the desert. :P (Not a predator, though.)

Once you have created a zoo that fulfills the animal's basic needs (thirst, hunger environment satisfaction, etc.), you must fulfill their advanced needs (Social, stimulation, etc.)and release at least ONE of each animal into the wild. Once you have satisfied all their basic needs, one more of each animal should have been delivered to the front of your zoo for company to the other animal. Unless you've already released one camel into the wild, you don't have to release the second one.

At the start pause and crate the animals then, delete everything including the pavement all the buildings and all the trees everything. Make sure your zoo is closed and for this challenge you wont need to open it up. Delete the existing exibits, and build them again 10x10 in a four square shape. Put the moose and camel side by side with a low fence between them and then thr cheetah and the gazelle side by side. All food water and the stables to the camel moose and gazelle (even though it does not recommend the stable for the moose) and the wooden shelter for the cheetah. Add three trees, 1 rock and 1 plant in the exhibits (I used the savannah trees for the scrub biome) and then put the animals in the exhibits. Automatic win once you hit resume. Won't even have to groom or heal the animals