The dogs quickly learned to avoid mule deer. The whitetail would run away. But the hybrids would walk up to the dogs, stop and lean away. Like a whitetail, most hybrid deer would wait until the danger was close before attempting to escape, but when they finally fled they'd often move only a short distance before stopping. Pausing to look back is a trait of mule deer, but mulies usually pause to study danger from a distance, not at close range.
Hybrids can survive as long as they remain with their mothers or if they're under human care.
But they cannot survive in the wild unless they're in an area with no predators. The exceptions to the rule are sandhills and badlands. In those terrains, Dr. Geist explains, mule deer does are able to escape the advances of rutting whitetail bucks by bounding up steep inclines whitetails tend to avoid. The problem is not, as some have suggested, that breeding whitetail bucks are more aggressive than mule deer bucks. A rutting mule deer will easily drive off a whitetail trying to infringe on its territory.