The Influence of Life History Milestones and Association Networks on Crop-Raiding Behavior in Male African Elephants

Factors that influence learning and the spread of behavior in wild animal populations are important for understanding species responses to changing environments and for species conservation. In populations of wildlife species that come into conflict with humans by raiding cultivated crops, simple models of exposure of individual animals to crops do not entirely explain the prevalence of crop raiding behavior. We investigated the influence of life history milestones using age and association patterns on the probability of being a crop raider among wild free ranging male African elephants; we focused on males because female elephants are not known to raid crops in our study population. We examined several features of an elephant association network; network density, community structure and association based on age similarity since they are known to influence the spread of behaviors in a population. We found that older males were more likely to be raiders than younger males, that males were more likely to be raiders when their closest associates were also raiders, and that males were more likely to be raiders when their second closest associates were raiders older than them. The male association network had sparse associations, a tendency for individuals similar in age and raiding status to associate, and a strong community structure. However, raiders were randomly distributed between communities. These features of the elephant association network may limit the spread of raiding behavior and likely determine the prevalence of raiding behavior in elephant populations. Our results suggest that social learning has a major influence on the acquisition of raiding behavior in younger males whereas life history factors are important drivers of raiding behavior in older males. Further, both life-history and network patterns may influence the acquisition and spread of complex behaviors in animal populations and provide insight on managing human-wildlife conflict

Seasonal variations of the digestive tract of the Eurasian beaver castor fiber.

Forage availability for wild rodents varies with season. In turn, the composition of food can affect morphometric parameters of the digestive tract. This study was performed in Eurasian beavers (Castor fiber) whose population was close to extinction in most Eurasian countries, but has now increased. Due to the previous low number of studies, information about the effect of forage availability on the digestive tract morphology has previously been lacking. This study was performed using beavers captured from the natural environment during three seasons of different forage availability: winter, summer and autumn. It was found that the diet of the beaver varied during the year; in winter it was dominated by woody material consisting of willow shoots, whereas in summer the diet was primarily herbs, grass and leaves. Season also affected the mass of digested contents of the digestive tract. The digestive content increased in the caecum and colon in winter and autumn, when poor-quality food dominated the beaver's diet. The results indicated that the digestive tract parameters of beavers varied based on the composition of available forage

Cultural Views of Breastfeeding Among High-School Female Students in Japan and the United States: A Survey

This study compares the attitudes toward breastfeeding of high-school students in Japan and the United States. The study was conducted as a cross-sectional survey with a convenience sample (N=329). Data were collected in 1989 and 1990 at two private, girls-only high schools (Tokyo, Japan and Farmington, Michigan). Retrieval rates were 100 percent (Tokyo) and 78 percent (Michigan) respectively. Responses were compared by the chi-square (x2) test with Yate's correction and factor analyses. Tokyo students perceived that their mothers talked positively about breastfeeding (54 percent), while only 17 percent of Michigan students reported that their mothers did so (<.001). Less than five percent of the Tokyo students felt that breastfeeding disturbs family life, whereas nearly 98 percent of the Michigan students felt so (p<.001). Tokyo students scored significantly higher on the 'family' factor, while the Michigan students scored significantly higher on the 'self factor. Overall, this study indicates that high school students in Japan have more positive attitudes toward breastfeeding than students in the United States; however, teenagers in the United States are more interested than their Japanese age-mates in gaining information about breastfeeding.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68653/2/10.1177_089033449401000124.pd