Аннотация:Most of the maternal motivation research procedures (home-cage testing, various learning techniques) require much time and manpower. We present a new express-method of the rats' maternal behavior assessment on the open field arena, which takes about 10 minutes per animal a day. During the first 2 minutes of the experiment we record the locomotor and exploratory activity under red light. Then three pups are placed in the center of the arena, and during the next 2 minutes we measure number and latencies of approaches and carryings of the newborns. During the last 2 minutes the pups are placed in the center again, but with the bright light on. The exploratory activity and locomotion on the postnatal days 4 to 6 reduced. Simultaneously the maternal reactions intensity significantly increased both under red and bright light. The parental care under bright light (which is more stressful) was more active. Large amount of animals (n = 74) allowed us to use the factor statistical analysis. It extracted the impact of defensive and exploratory motivations, which competed with the maternal care across the three days of testing, on the rats' reactions. Our method also provides important information about active and passive components of the mother-pup interaction and reveals the learning process based on the maternal motivation.