Attack and defense in conspecific fighting in tree shrews (Tupaia belangeri)

Principles of conspecific defense have been analyzed for rodents, in which specific target sites for biting by attackers on defenders serve as an impo rtant determinant of the actions involved in both attacker and defender beh avior. In an effort to determine the generality of these principles, attack and defensive behaviors and target sites fur biting attack were evaluated in a nonrodent species, the tree shrew (Tupaia belangeri). Brief daily and repeated conspecific dyadic encounters between adult, socially experienced males (dominants, attackers), and adult, socially naive males (subordinates , defenders) that had been transferred into the territory of the dominants, produced a polarization of attack and defense. The dominant males showed c hase, chase attack,jump attack, and biting behaviors, while the subordinate s displayed night and freezing. The vast majority of bites, as well as woun ds and bruises, were on the subordinates' backs, These patterns are very si milar to those previously found in rats and mice and suggest that the organ ization of fighting, with targets of biting (or other painful) attack servi ng as an important determinant of both attacker (dominant) and defender (su bordinate) behavior, may show considerable generality across nonrodent as w ell as rodent species. Although relatively few wounds were found after 28 d ays of repeated and daily encounters, the subordinate tree shrews show a va riety of behavioral, neuroendocrine, and central nervous changes, indicatin g that they are stressed by these encounters per se. (C) 2001 Wiley-Liss, I nc.