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Although the field of urban evolutionary ecology has recently expanded, much progress has been made in identifying adaptations that arise as a result of selective pressures within these unique environments. However, as studies within urban environments have rapidly increased, researchers have recognized that there are challenges and opportunities in characterizing urban adaptation. Some of these challenges are a consequence of increased direct and indirect human influence, which compounds long-recognized issues with research on adaptive evolution more generally. In this perspective, we discuss several common research challenges to urban adaptation related to (1) methodological approaches, (2) trait–environment relationships and the natural history of organisms, (3) agents and targets of selection, and (4) habitat heterogeneity. Ignoring these challenges may lead to misconceptions and further impede our ability to draw conclusions regarding evolutionary and ecological processes in urban environments. Our goal is to first shed light on the conceptual challenges of conducting urban adaptation research to help avoid the propagation of these misconceptions. We further summarize potential strategies to move forward productively to construct a more comprehensive picture of urban adaptation, and discuss how urban environments also offer unique opportunities and applications for adaptation research.

As the human population increases, urban areas are expanding and bringing humans and wildlife into close proximity. Disturbance by humans can lead to changes in animal behavior and ecological interactions. Urban areas also provide access to novel, artificial substrates (e.g., cement walls and metal posts), which may influence the behavior of organisms. We studied whether urban habitats and artificial substrates influenced escape and foraging behavior of the Puerto Rican Crested Anole (Anolis cristatellus). We tested whether lizards in urban environments reduced flight initiation distance (i.e., the distance between the observer and the lizard when the lizard begins escape) in response to differences between the natural habitat and whether flight distance differed between urban and natural habitats. We found that flight initiation distance was significantly shorter in urban environments as compared to forest habitats. Flight distance did not differ between habitats. The proportion of escape modes used varied between the habitats. Urban lizards escaped more frequently by squirreling around the perch and reduced the frequency of jumping. Use of larger perches with less vegetation nearby in urban areas was consistent with our results of lizard's squirreling more and jumping less during escape. Our results show differences in lizard flight initiation and escape mode employed between the urban and natural habitats. Habituation to the presence of humans and/or lower predation risk could account for differences in FID. Moreover, habitat differences in urban areas influence the escape mode used by lizards through the increased availability of larger perches and the reduction of perches to which lizards can jump. We tested differences in latency to feed between urban and forest environments and in the presence or absence of a life-like model of a lizard predator. We found that lizards in the forest habitat foraged more frequently and faster compared to lizards in the urban ar