Despite over a century of interest, the function of zebra stripes has never been examined systematically. Here we match variation in striping of equid species and subspecies to geographic range overlap of environmental variables in multifactor models controlling for phylogeny to simultaneously test the five major explanations for this infamous colouration. For subspecies, there are significant associations between our proxy for tabanid biting fly annoyance and most striping measures (facial and neck stripe number, flank and rump striping, leg stripe intensity and shadow striping), and between belly stripe number and tsetse fly distribution, several of which are replicated at the species level. Conversely, there is no consistent support for camouflage, predator avoidance, heat management or social interaction hypotheses. Susceptibility to ectoparasite attack is discussed in relation to short coat hair, disease transmission and blood loss. A solution to the riddle of zebra stripes, discussed by Wallace and Darwin, is at hand.

a b s t r a c tEffective conservation planning relies on the accurate identification of anthropogenic land cover. However, accessing localized information can be difficult or impossible in developing countries. Additionally, global medium-resolution land use land cover datasets may be insufficient for conservation planning purposes at the scale of a country or smaller. We thus introduce a new tool, GE Grids, to bridge this gap. This tool creates an interactive user-specified binary grid laid over Google Earth's high-resolution imagery. Using GE Grids, we manually identified anthropogenic land conversion across East Africa and compared this against available land cover datasets. Nearly 30% of East Africa is converted to anthropogenic land cover. The two highest-resolution comparative datasets have the greatest agreement with our own at the regional extent, despite having as low as 44% agreement at the country level. We achieved 83% consistency among users. GE Grids is intended to complement existing remote sensing datasets at local scales.

Over 40 states have considered voter identification laws in recent years, with several adopting laws requiring voters to show a valid ID before they cast a ballot. We argue that such laws have a disenfranchising affect on racial and ethnic minorities, who are less likely than Whites to possess a valid ID. Leveraging a unique national dataset, we offer a comprehensive portrait of who does and does not have access to a valid piece of voter identification. We find clear evidence that people of color are less likely to have an ID. Moreover, these disparities persist after controlling for a host of relevant covariates.

A growing body of research explores the influence of involuntary criminal justice contact on political participation, demonstrating that all types of contact weaken political participation. We posit, however, that personal connections to civil society organizations (CSOs) moderate the negative effects of involuntary criminal justice contact on political participation, particularly political activism beyond registering to vote and voting. We test this proposition with individual-level and aggregate-level data from metropolitan and municipal Chicago. Our findings confirm a paradox of participation by custodial citizens. One, we demonstrate positive, statistically significant, and substantive effects of personal connections to CSOs on nonvoting political participation by custodial citizens. Two, the negative effects of involuntary criminal justice contact on voting participation among individuals and communities may endure, despite personal connections to CSOs, even in a state where the franchise is restored immediately after incarceration. Our study suggests that an associational account of political participation deepens our understanding of the political behavior of custodial citizens and their communities in the age of mass incarceration.

Anecdotal evidence suggests that Muslim American women who wear the hijab may be particularly vulnerable to the experiences of stigmatization because the hijab represents one of the most obvious and dominant markers of “otherness.” Yet, extant research has surprisingly neglected to systematically examine how such external markers of difference can increase perceptions of discrimination. Drawing from two nationally representative datasets, we examine perceived discrimination among Muslim Americans, and find that veiled women report experiencing both societal and institutional discrimination at much higher rates than their counterparts. In fact, our findings show that the hijab is one of the most important predictors of self-reported discrimination among all Muslim Americans. Interestingly, however, we also find that men are more likely than women to perceive discrimination once we account for the role of the hijab. Our analysis makes an important contribution to existing research by highlighting the unique experiences of a religious minority group and identifies one important and previously underexplored mechanism by which individuals may be targeted for discrimination—the hijab.