Behavioral biology and operant psychology have developed in parallel but separate paths since their origins in the 1930s. In the first three decades, both fields dealt with microscopic (or molecular) controlling variables and qualitative data. Since about 1960, both have primarily focused on macroscopic (or molar) controlling variables. Their shared interest in foraging in the 1980s suggests a limited convergence beween biologists and psychologists in data, methods, and theories. We draw on accounts of intertheoretic relations from the philosophy of science, including both interlevel theory and interfield theory, to understand this convergence. However, our greater emphasis on methods of data collection and analysis leads us to characterize the convergence as not only one of interfield theory but one of interfield science.