Climbing test to measure gross motor development in monkeys

This report describes an apparatus, protocol, and coding procedure to quantify gross motor skills in infant Macaca nemestrina, and presents data obtained from this system. The apparatus consists of a 1.8-m-tall Plexiglas tube extending from the top of a standard stainless steel cage. Animals climb the tube to reach a food reward. Measures of climbing ability included time and number of contacts with the tube. Data were collected on 336 climbs to the highest level (1.5 m) on eight normal infants. Three subjects began training at two months of age, three began at three months, and two began at four months. Exploratory data analysis revealed that Time Up was the best measure due to low variability between and within subjects, high motivation of the subjects to reach the food reward, and ease of measurement. Though this pilot study is based upon a limited sample size, two-month-olds were consistently slower and more variable than the three- and four-month-olds. Relatively few sessions are required to train the subject and obtain measures of a subject's motor ability. The advantages of the climbing tube are that it is inexpensive to operate, provides a large amount of data, and appeals to the subject's natural propensity to climb. © 1995 Wiley-Liss, Inc.