Large home ranges and extreme flexibility in ranging behaviors characterize most subarid dwelling haplorhines. However, the most comparable extant strepsirhine, Lemur catta, is characterized as having small home ranges with consistent boundaries. Since ranging studies on this species have been limited to gallery forest habitat, the author's goal is to identify ecological factors that affect range use of L. catta in one of the most resource-limited environments of its distribution. To conduct this study, ranging and behavioral data were collected on two nonoverlapping groups through all-day follows in the semidesert scrub environment of Cap Sainte-Marie (CSM), Madagascar. Data were collected from August 2007 through July 2008. Home range areas and day range lengths were generated using ArcGIS® 9.3. Other variables measured were habitat composition, diet richness, daily activity, and microclimate. Home range areas of CSM L. catta were very large relative to those of gallery forest L. catta, and there was great monthly variation. In contrast, day range lengths at CSM were either smaller than or approximated the size of comparative gallery forest groups. Temperature, sunning, and diet richness were associated with day range length for one but not for both groups and appear to be related to energy management needs. Based on these findings, the author suggests that L. catta is capable of extensive behavioral and ranging flexibility in the extremes of its environment. However, physiological constraints impose limitations that can interfere with its ability to adapt to even seemingly minor variations in microclimate and habitat structure within the same site. Am J Phys Anthropol, 2013. © 2012 Wiley Periodicals, Inc.