Reproductive Characteristics of Alaskan Moose

Many aspects of moose (Alces alces) reproduction are poorly documented. Therefore, we quantified the estrous cycle, estrous length, gestation period, fetal development, and birth mass of calves. We evaluated empirical relationships among maternal age, mass, and previous breeding parity with litter size and neonatal sex ratio. Increased attentiveness by the bull signaled estrous behavior in cows. Estrous females did not increase activity. The estrous cycle varied from 22 to 28 days (x = 24.4 days) and did not lengthen with each successive cycle. The cycle of primiparous females was shorter (P = 0.05) than pluriparous females. Gestation averaged 231 days (SD = 5.4 days) and did not differ (P > 0.05) between primiparous and pluriparous females, litters of 1 or 2 calves, among 5 years of study, or between cows bred their first or second overt estrus