Toward a behavioral ecology of rescue behavior.

Although the study of helping behavior has revolutionized the field of behavioral ecology, scientific examination of rescue behavior remains extremely rare, except perhaps in ants, having been described as early as 1874. Nonetheless, recent work in our laboratories has revealed several new patterns of rescue behavior that appear to be much more complex than previously studied forms. This precisely-directed rescue behavior bears a remarkable resemblance to what has been labeled empathy in rats, and thus raises numerous philosophical and theoretical questions: How should rescue behavior (or empathy) be defined? What distinguishes rescue from other forms of altruism? In what ways is rescue behavior in ants different from, and similar to, rescue in other non-human animals? What selection pressures dictate its appearance? In this paper, we review our own experimental studies of rescue in both laboratory and field, which, taken together, begin to reveal some of the behavioral ecological conditions that likely have given rise to rescue behavior in ants. Against this background, we also address important theoretical questions involving rescue, including those outlined above. In this way, we hope not only to encourage further experimental analysis of rescue behavior, but also to highlight important similarities and differences in very distant taxa.