ABSTRACT
Among the topics included under the general category of numerical abilities are the numeri cal operations (addition, subtraction, multipli cation, and division), estimation (used for large numbers such as crowds), and counting (specific enumeration of items). A very exciting feature of counting is that it is a relatively high-order and interesting cognitive process that may be investigated without too much difficulty in a wide variety of nonverbal organisms including human infants, chimpanzees, monkeys, rats, and birds. Although scientific investigation of animal counting occurred as early as the 1920s (see Rilling, 1993), recent times have witnessed an explosion of interest in the topic, possibly facilitated by a review of the animal counting literature by Davis and Memmott (1982).
