Aggressive and Affiliative Behavior in Green Monkeys With Differing Housing Complexity

Eleven green monkeys (Cercopithecus aethiops) were combined into three social groups (two heterosexual, one all-male) in enclosures with similar volume but different levels of environmental complexity (two or four compartments). Agonistic and affiliative interactions were recorded over a 21-week period. The two heterosexual groups had their environmental complexity reduced (number of compartments reduced by one-half […]

Within-group social relationships among females and adult males in wild western lowland gorillas (Gorilla gorilla gorilla)

Within-group female relationships, and relationships between females and adult males have not been described for wild western lowland gorillas. New data are presented here from Mbeli Bai in the Nouabale´-Ndoki National Park, Republic of Congo. Nine groups were observed over a continuous 2-year period, and affiliative and agonistic interactions, as well as time spent by […]

Fighting dynamics of male copperheads,Agkistrodon contortrix (Serpentes, Viperidae): Stress-induced inhibition of sexual behavior in losers

Abstract 10.1002/(SICI)1098-2361(1996)15:33.3.CO;2-E Adult male copperheads (Agkistrodon contortrix) fight for priority of access to females during the mating periods in spring and late summer. During fights, one male abruptly quits and retreats, and the other chases in pursuit. One male thus emerges as the winner and the other as the loser. Reversal of this outcome does […]

Female crickets are driven to fight by the male courting and calling songs

Crickets have traditional sex roles, where males compete aggressively for access to selective polyandrous females. However, in a laboratory experiment, we found that normally nonaggressive female Gryllus campestris fought each other vigorously in the presence of a courting male, resulting in a dominant female that gained a greater probability of receiving the spermatophore. Female-female fights […]

Male morphs in tree lizards have different testosterone responses to elevated levels of corticosterone

Changes in circulating glucocorticoid and androgen levels mediate agonistic behaviors in many vertebrates. Individual variation in the magnitude of the glucocorticoid response to stressful stimuli, the negative effects of elevated glucocorticoid levels on androgen levels, or both could mediate individual differences in subsequent agonistic behavior. In a series of previous studies, we found that both […]

Grooming and coalitions in Japanese macaques (Macaca fuscata): Partner choice and the time frame reciprocation

Evidence of a reciprocal exchange of grooming and agonistic support in primates is mixed. In this study, the authors analyzed a large database of grooming and coalitions in captive female Japanese macaques (Macaca fuscata) to investigate their within-group distribution and temporal relations. Macaques groomed preferentially those individuals that groomed them most and supported preferentially those […]

Female meadow voles (Microtus pennsylvanicus) demonstrate same-sex partner preferences

Female meadow voles (Microtus pennsylvanicus) are territorial during warm months but demonstrate social tolerance under low temperatures. In spring, females nest together and some pairs participate in communal nursing and rearing of young. Because communal nursing involves significant cooperation, selective pair-bonds may develop between 2 nestmates. Using a choice apparatus, the authors determined that (a) […]

Affiliative and aggressive behavior in a group of female somali wild ass (Equus africanus somalicus)

We observed a group of three young female Somali wild asses to develop an ethogram of social behavior in the first phase of a longer term study of social, sexual, and maternal/infant behavior. The most unexpected finding was the frequency and extent of aggressive interactions, which included Charge, Drive, Neck Wrestle, Head Butt, and Body […]

Exposure to the steroid hormone 20-hydroxyecdysone modulates agonistic interactions in male Homarus americanus

In this study we present evidence that 20-hydroxyecdysone (20E) affects agonistic behavior in male American lobsters and that male and female animals differ in their response to the hormone. Thirty-minute staged fights were conducted between large males exposed either to artificial seawater (ASW) or 20E and small, anosmic opponents. The nephropores of both combatants were […]

‘Roid rage in rats? Testosterone effects on aggressive motivation, impulsivity and tyrosine hydroxylase

Abstract In humans and animals, anabolic-androgenic steroids (AAS) increase aggression, but the underlying behavioral mechanisms are unclear. AAS may increase the motivation to fight. Alternatively, AAS may increase impulsive behavior, consistent with the popular image of ‘roid rage. To test this, adolescent male rats were treated chronically with testosterone (7.5 mg/kg) or vehicle and tested […]