9709212 Packer This project will analyze the extent to which male and female lions invest in the survival of offspring. Under most conditions, male lions compete for food with the rest of their pride, but resident males provide important defense against extra- group males. Pridemates forage apart and males spend considerable effort trying to relocate the females and young. Females should be most likely to reveal their whereabouts to resident males when their cubs are in greatest need of protection from infanticidal strangers but least helpful when feeding competition would be most intense. Females are also expected to weigh the relative reproductive value of successive broods according to the vulnerability of their younger cubs, being more likely to resume exclusive investment in their older brood when the younger brood is virtually doomed. Because male parental investment is so important to cub survival, this research is directed at examining factors related to male-female cooperation and mating behaviors, and includes a series of mate-choice and intruder- simulation experiments. Females are predicted to prefer to mate with males with larger or darker manes, whereas males should preferentially attack strangers with shorter or lighter manes. The study will investigate whether the mane is a condition-dependent trait, and will examine a variety of nutritional and hormonal factors that are likely to contribute to variability in mane size and color. Studies will be conducted in the field at the NSF Long-Term Ecological Research site in the Gombe National Park, Tanzania. Results of this research will allow a better understanding of the evolutionary factors underlying the complex social behavior of lions.
