A literature survey was conducted to find papers that reported pig behavior during the period 1987 to June 1990. A total of 171 papers reporting measures of pig behavior was identified. Investigators used either descriptions of behavior or they quantified behavior. Behavior was quantified by recording frequency, durations, sequences, or bouts of behavior. Sexual behavior was often recorded as an all-or-none event (e.g., they were bred or not). Feeding behavior was studied by either weighing feeders often or by operant techniques. Operant feeding devices were commonly used to study pig feeding and drinking behaviors. Social behavior was studied either as interactions among established groups or when pigs fought after grouping. In either case, behavioral frequencies or durations were often reported. A large number of papers documented studies of maternal-neonatal interactions, teat orders, and animal care issues. Only a few studies reported mechanisms controlling pig behavior. Because few studies investigated behavior-genetics or physiological mechanisms controlling pig behavior, these areas of investigation hold great opportunity for future improvements in pork production.