We used indirect respiration calorimetry to measure seasonal metabolism and lower critical temperatures (TLC) of eastern coyotes (Canis latrans var.). The yearly mean basal metabolic rate was 10.6 L O2∙kg−1∙d−1. No difference was found among seasonal BMRs. The TLC values were 10, 0, and 5 °C during summer, autumn, and spring, respectively. Metabolism increased linearly below the TLC values. Normal temperatures in New Hampshire were well within the seasonal thermoneutral zones of eastern coyotes. The average daily energy requirements of free-ranging eastern coyotes during winter were estimated as 163.5 kcal∙kg−1 (3 × BMR). A 15-kg coyote required three snowshoe hares (Lepus americanus) every 2 days to satisfy these energy needs. In northern forested habitats, where hare and white-tailed deer (Odocoileus virginianus) may represent the primary prey species, interrelationships of the energy requirements of eastern coyotes with coyote breeding activity, sociality, and snow conditions may favor predation of white-tailed deer during late winter, particularly if hare availability is low.