The sled dog one was covered in the original article, so I didn't repeat it here. ("Huskies can trot up to 100 kilometers in Arctic conditions when forced to by people. But in warmer climes—no way.")

I have been unsuccessful in finding good endurance times for these animals. http://www.jordanjubilee.com/outdoors/camels.htm claims "A very good camel can cover 120 or 130kms in 12 hours. Some specially bred camels have been known to continue at racing speed for up to 18 hours."

Getting similar times for ostrich and pronghorn antelope, which don't have jockeys and even less reason to run for 12 hours straight, would be much harder. While doable, there's little fame or money reward for doing so, which means the observations are based on the average fastest speed for the species, and not the fastest of the fastest like it is for humans.

Oh, and I wonder if a specially prepared road or track would give better times for a camel; the human times you quoted are on roads or tracks, not cross-country like the camel races.

Anyone who has put sled dogs in harness know that they are extremely eager and don't need coaxing. They also go far further than 100km speeds well beyond what people can do. The dogs lose their underfur in summer and can cover long distances then too (you can see this if you do a river trip with the dogs running on the riverbank). You'll also see wolves sometimes cover huge distances very quickly, regardless of season. Lack of a summer race does not indicate that those animals are not capable of it.

Fair point about the road/track being more efficient than overland. People move much more slowly on the Iditarod trail whether on bike, skis, or running (http://www.alaskaultrasport.com/).