Final answer:
The net calories a mule deer gets from sage brush vary based on factors like the nutritional content of the plant and the deer's digestive efficiency. Exact caloric values would require controlled measurements.
Step-by-step explanation:
The number of net calories a mule deer obtains from consuming sagebrush is not a fixed value, as it can vary based on several factors, including the nutritional content of the sagebrush, the efficiency of the deer's digestive system, and any energy expended in the process of obtaining and consuming the plant.
Sagebrush is a common component of a mule deer's winter diet when other food sources are scarce, although it is not as energy-rich as some other food sources that might be available. The exact caloric intake would require specific measurement under controlled conditions. However, it's important for the deer to balance their energy intake with their energy expenditures to maintain their health, especially during the harsh winter months.