This paper is primarily concerned with two attributes of the open-field test of emotionality. The first concerns the generality of the behavior patterns elicited by the open-field to animals of different species and ages. The second is concerned with how the two most commonly used indices of emotionality, activity and defecation, correspond to change in heart rate, a physiological measure sometimes proposed as an indicator of emotionality. Both attributes are important if one questions the validity and reliability of the open-field test as a general measure of emotionality in a variety of animals. It is likely that the behaviors elicited by the open-field vary according to the species tested, since species probably differ in the display of their characteristic syndromes of emotionality. This paper reports comparisons of open-field behavior elicited from several disparate species.