With the advent of global position system (GPS) collar technology, we have developed a much greater understanding of the temporal and spatial distribution of livestock and their associated grazing patterns. While significant research using GPS collars has been reported for cattle, little research is available describing collar use in understanding the behavior of domestic sheep. The purpose of our research was to evaluate the energy requirements of sheep with the use of GPS collars. To accomplish this, we adapted a low-cost i-gotU GPS tracking device that is typically designed for cattle and modified it to fit sheep. Each collar was programmed to record sheep movements within four grazing habitat types during different times of the year. Habitat types included spring pasture (SP), spring low hill habitat (SH), summer mountain habitat (MH) and winter desert habitat (DH). We divided our research into two studies: 1) to track and compare energy expenditure of domestic sheep between four habitats using collars for recording sheep movements, and 2) to model summer mountain selection by sheep using the collar derived coordinate positions and environmental variables in an RSF model process. We hypothesized that there would more energy expended while out on desert habitat in comparison to other range habitats and sheep would select for sites on summer mountain habitat that were close to water, gentle in terrain, and higher in elevation. We used sheep energy equations to determine the energy requirement. Collar derived coordinates were used to measure the horizontal distance traveled on flat terrain or vertical distances both upslope and downhill across variable terrain. Our results found that total distance traveled was not different between SP, SH and MH at 6.7, 7.1 and 6.9 km/d, respectively, however, total movement was different (P<0.05) on DH at 10.5 km/d. Sheep movement was greater (P<0.05) on slopes (altitude change in 3m between waypoints) versus flat terrain (movement between waypoints >20m). For example, sheep spent 65% of movement on slope and 39% on flat movement for SH, 86% of movement was spent on slope and 16% on flat terrain for MH, and 89% of movement was spent on slope and 11% movement was on flat for DH. Total energy required between the four habitats was different (P<0.05) at 5.9, 8.6, 7.1 and 13.9 Mcal ME/d for SP, SH, MH and DH respectively. While on summer MH sheep avoided slopes and rugged terrain, but selected for sites close to water, northern facing aspects and areas higher in elevation. We found that sheep expend the most energy on DH and sheep on MH will select for gentle terrain, areas close to water, northern facing slopes, higher elevation and avoid slopes. With this insight, sheep managers can better meet energy requirements needs and understand habitat utilization of their flocks.