Relation between social rank, submissive behavior, and brain catecholamine levels in ring-necked pheasants (Phasianus cholchicus).

Abstract

In Experiment 1, the social hierarchy of 23 male ring-necked pheasants (Phasianus colchicus) was found to be linear except for positions in the middle ranks. Social rank was inversely correlated with submissive ("supercedent") behavior but was unrelated to size (weight) of the birds. In Experiment 2, with 8 cock pheasants, general activity of the birds was not correlated with social rank or supercedent behavior. These data suggest that the spatial displacement of one individual by another is not a random or neutral social process, or a function of size differences among birds. The catecholamine concentrations in several brain structures were determined. Only dopamine concentrations in the neostriatum of high-ranking males were reliably different (higher) from concentrations of low-ranking males. These concentrations were inversely correlated with supercedent behavior. These findings are discussed in terms of other pharmacological, neuroanatomical, and behavioral data.