摘要:

AbstractTo determine how pigs assess their relative fighting ability, I observed paired contests between young pigs that were either of similar weight or of different weight. On the first day the incidence of fighting was high, but this was not affected by the size of the weight difference. Fights between pigs of different weight were shorter than those between pigs of similar weight. When the pigs were of different weight, the eventual winner bit more frequently and spent more time attacking than did the eventual loser. This difference was not apparent when the pigs were of similar weight. On the first day, winners and losers were equally likely to initiate fights. The incidence of fighting was lower on the second day, although this was unaffected by the weight difference. Losers were less likely to initiate fights on the second day, and fights were shorter than on the first day. However, for the time that they did fight, the losers fought as vigorously (based on the rate of biting) on the second day as on the first. Seventy‐two hours of visual and olfactory contact before the fight had no effect on the incidence of fighting and minimal effect on its duration. I suggest a young pig cannot assess its chance of success prior to the first encounter but only during the course of the fight. This assessment is reduced by attacks from the opponent until it drops below a critical threshold, whereupon the pig stops fighting. As a result of a previous defeat, a pig will lower its assessment and will be less likely to fight or to initiate fights on subsequent encounters. It is this change in assessment rather than habituation alone that makes pigs less likely to fight as they become acquainte

ISSN:0096-140X    

DOI:10.1002/1098-2337(1988)14:3<155::AID-AB2480140302>3.0.CO;2-T

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractDefensive aggression was examined in seven species of terns during the hatching period when young are most vulnerable and adults most responsive. Aggression toward an unfamiliar person varied with respect to species, flush distance, approach distance, number of birds overhead and diving, and number of dives per 2 min for all birds and the nest owner. Defensive aggression involved birds circling over and diving at the experimenter. Generally, flush distance was negatively correlated with nest density, while the number of birds diving was positively correlated with the nest density. The number of birds diving was positively related to the number of dives, dives by the owner, and the number overhead.

ISSN:0096-140X    

DOI:10.1002/1098-2337(1988)14:3<169::AID-AB2480140303>3.0.CO;2-D

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractLaboratory rats were used to investigate sex and strain differences in the effects of aggression on a cooperative behavior in which pairs learn to coordinate shuttling in a rectangular chamber. The level of aggression was manipulated by comparing males and females of the aggressive S3 strain and a less aggressive Sprague‐Dawley‐derived strain and by housing same‐sex partners either together or individually (eight groups, n = 7 pairs per group). Hormone levels were stabilized by gonadectomy and daily injections of the appropriate sex hormone. The only serious coordination deficits were in individually housed males, associated with violent fighting and an extreme dominance/subordinance relationship that was not observed in females. All other groups readily learned and performed the coordination, with evidence that low and moderate levels of aggression could facilitate coordination by evoking species‐typical behaviors that increased proximity, synchrony, and differentiation within pairs. The discussion focused on models of affiliative behavior in the study of aggression and the compatibility between moderate levels of aggression and coop

ISSN:0096-140X    

DOI:10.1002/1098-2337(1988)14:3<179::AID-AB2480140304>3.0.CO;2-9

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractMale rats exhibiting high, moderate, or low levels of offensive aggressive behavior in interactions with intruders in their home cage were grouped in mixed‐sex colonies with 1 male of each aggression‐level group in each colony. Agonistic interactions measured 1, 2, 3, 7, 14, 21, and 22 days after colony formation indicated that highly aggressive males on pretests continued to be more aggressive, becoming the dominant colony male in five of seven colonies and attacking intruders more often than less aggressive males. In the two remaining colonies the moderately aggressive male became dominant. This relationship, which was consistent over a number of indices, including offensive and defensive behaviors, and wound counts and wound sites, was seen even when a substantial weight differential favored the less aggressive animal. Dominance relationships were rapidly established and within‐group fighting declined significantly over the 21‐day test period.Pretest offensive levels also influenced the behavior of subordinates, with high or moderately aggressive subordinates showing more defense in interactions with dominants and receiving more wounds than did low‐aggression subordinates. Dominant males also showed more defense in interacting with those subordinates which had been more aggressive during pretests. This pattern of results suggests that aggression level of the subordinate as well as the dominant may be an important factor determining the intensity of agonistic interactions in

ISSN:0096-140X    

DOI:10.1002/1098-2337(1988)14:3<195::AID-AB2480140305>3.0.CO;2-G

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe influence of the social rank of male mice, determined by the outcome of fights, was assessed on their growth, treadmill performance, open‐field behavior, and morphometric traits. Fertility of mated females was also investigated. Special attention was paid to the relationship between the male's social rank and body weight. Winners of fights were heavier than losers; their latencies were shorter, and they showed more locomotor activity in an open field test. Winners also had higher absolute testicular and epididymal weights. These males had a positive influence on the reproductive fitness of the females with which they were mate

ISSN:0096-140X    

DOI:10.1002/1098-2337(1988)14:3<205::AID-AB2480140306>3.0.CO;2-J

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractLactating mice respond differently to male and female conspecific intruders, displaying defensive attack towards the former and offensive attack towards the latter. Two studies are reported in which the effects of naloxone on this differential response pattern were assessed. In the first study, lactating residents were pretreated with saline or naloxone (0.5, 2.5 mg/kg) and consecutively confronted with intruders of differing sex. Results suggested that attack (offensive) against female conspecifics is more sensitive to the inhibitory effects of opiate‐receptor blockade than attack (defensive) on males. This conclusion was strengthened in a follow‐up study, in which independent groups of lactating residents were used to further examine the effects of naloxone (0.5 mg/kg) on response to male and female intrusion. Analysis indicated that this low dose of naloxone significantly inhibited attack on female, but not on male, intruders. Indeed, in response to male, but not to female, intrusion, naloxone‐treated residents showed a significant increase in fear‐related behaviour. Findings are discussed in relation to the motivational differences in the response of lactating mice to intruders of differing sex and to possible mechanisms underlying the reported differential effects of opiate‐receptor

ISSN:0096-140X    

DOI:10.1002/1098-2337(1988)14:3<213::AID-AB2480140307>3.0.CO;2-L

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

ISSN:0096-140X    

DOI:10.1002/1098-2337(1988)14:3<225::AID-AB2480140308>3.0.CO;2-B

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

ISSN:0096-140X    

DOI:10.1002/1098-2337(1988)14:3<226::AID-AB2480140309>3.0.CO;2-5

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

ISSN:0096-140X    

DOI:10.1002/1098-2337(1988)14:3<229::AID-AB2480140310>3.0.CO;2-M

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

ISSN:0096-140X    

DOI:10.1002/1098-2337(1988)14:3<230::AID-AB2480140311>3.0.CO;2-8

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY