Some Aspects of the Dominance-Subordination Relationship in the Fish Platypoecilus maculatus

Abstract

Small homosexual or heterosexual groups of Platypoecilus fishes exhibit nip-right behavior. The fishes form hierarchies based upon individual contact-pair relationships which are established by challenging and fighting. The hierarchies show a tendency toward the true straight-line type, but incomplete hierarchies and triangle situations are common. After initial hierarchies are established, the social behavior of the fishes is less savage than during the formative period. Under the conditions of these observations all contact relationships tended to be short-lived and were characterized by frequent reversals, due to revolts. Established societies are characterized by alternating periods of activity and inactivity. Despots of either sex will interfere with the contact reactions of their subordinates. A despot of either sex nips its subordinates differentially as individuals and not according to their several ranks. Males are less social than [female][female]. They nip less but more savagely, move about less, and their hierarchies are less stable. In heterosexual groups [male][male] and [female][female] nip individuals of both sexes except during breeding periods, when [male][male] tend to limit their nipping to other [male][male]. In heterosexual groups the differences between [male] and [female] behavior are similar to those in homosexual groups but are less marked. Males tend to occupy the higher ranks in heterosexual hierarchies. The amt. of nipping done by a fish corresponds to its rank. A strange fish reacts submissively to all members of an established society. They, in turn, react aggressively toward the stranger. No evidence of territorial behavior was noted. Some evidence exists that the fishes recognize each other as individuals. Factors involved in dominance are: general aggressiveness and other psychological factors, size, male-ness, and factors as yet unknown.