Gerald C. Ruppenthal

Digital data acquisition systems for observing behavior in laboratory and field settings

Electronic digital systems for recording behavior and for record keeping in hospital, clinical, laboratory, and field settings are now available from commercial sources. Behavioral events, occurring in real time, are coded by an observer who pushes buttons on an adding machine-type keyboard. Information is stored electronically on a cassette or other type of magnetic tape recorder. Tapes can be played, through appropriate interfaces, into a computer, keypunch, Teletype punch, or digital printer. Code frequencies, sequences, real-time durations, and modified frequency time-sample scores can be extracted from these records by hand or by-computer. This paper describes such systems, detailing methods of coding behavioral events and problems encountered in the use of digital observational systems.

Weaning, body weight, and postpartum amenorrhea duration in pigtailed macaques (Macaca nemestrina).

Early permanent infant separation or weaning decreases the time interval between pregnancies and interbirth intervals for many female primates. At least part of the interpregnancy interval consists of postpartum amenorrhea, a period of non‐menstruation lasting from the time of birth until the female begins to ovulate. This study investigated the effects of weaning age and dam’s body weight on the duration of the interval between pregnancies, the duration of postpartum amenorrhea, and the number of cycles to conception in a year‐round breeder. Female pigtailed macaques (Macaca nemestrina) have an observable perineal swelling that fluctuates throughout the menstrual cycle and provides a means of detecting ovulation. The perineal swelling records of socially housed pigtailed macaques were studied from July 1996 to September 1998. Postpartum amenorrhea data were obtained on 44 females who gave birth to normal, viable infants. As weaning age increased and dam’s weight decreased, postpartum amenorrhea, and consequently the interval between pregnancies, increased in duration. The interpregnancy interval consisted almost entirely of the postpartum amenorrhea phase. Our finding that a higher dam’s body weight decreased the length of postpartum amenorrhea duration lends support to the hypothesis that a minimum body weight is necessary for menstrual cycles to occur. Most females became pregnant on their first ovulation regardless of weaning age and whether or not they were carrying an infant. As the weaning age of the infant and the dam’s weight increased, ovulation went from occurring after separation to occurring before separation. Am. J. Primatol. 52:81–91, 2000.

The Effects of Total Social Isolation Rearing on Behavior of Rhesus and Pigtail Macaques

Rhesus monkeys (M. mulatta) raised in social isolation exhibit a variety of post-rearing abnormalities which are so consistent that they have been termed “The Isolation Syndrome” (Sackett and Ruppenthal, 1973). This syndrome includes deviant personal behavior such as body rocking, self-clutching, peculiar postures, stereotyped locomotion, self-directed aggression, and a type of “waxy flexibility” in which an arm or a leg floats upward uncoordinated with other ongoing behavior. Isolates are also low in exploratory behavior, have almost no positive social interaction, and are abnormal as adults in sexual and maternal behavior. The only major type of behavior not showing pronounced abnormality is learning. Compared with socialized controls including wild-born monkeys, rhesus isolates are not deficient in discrimination, delayed response, or learning set performance (Gluck and Harlow, 1971; Harlow, et al., 1968).

Nursery Care of At-Risk Nonhuman Primates

The Infant Primate Research Laboratory (IPRL) at the University of Washington was established in 1970 to support scientific and medical investigations that require infant nonhuman primates as subjects. In a short time an “Infant Save” program was established to care for Primate Center Colony infants with a low survival probability if they remained with their mothers in their natal social groups. Neonates qualified for the program based on low birth weight and/or prematurity, inadequate maternal care or rejection, injury, or failure to thrive. All IPRL infants, including those assigned to almost all research projects, received daily socialization in play groups. In addition, the Infant Save monkeys were utilized to develop reflex, motor, and cognitive assessment methods and to investigate aspects of feeding, care, and housing to reduce morbidity and mortality. A major goal was to develop methods that did not confound experimental studies.