Aggression by a female rat cohabitating with a sterile male: termination of pseudopregnancy does not abolish aggression.
At the end of that time, each female was assessed for aggressiveness toward an unfamiliar female intruder once each week for 3 weeks. Those females displaying a high level of aggression had their male cagemate changed. For half of the females, the new male cagemate was a castrated male with a testosterone implant. For the other half, the new cagemate was a castrated male without a testosterone implant. Replacement males had been subjected to surgery 9 weeks previously. There were no differences in the aggressiveness of females of the two groups on any of 3 subsequent weekly tests of aggression. In a 3-h evaluation of male sexual behavior, none of the 9 castrated males without testosterone replacement displayed sexual activity with an estrogen/progesterone primed ovariectomized female, but 6 of 9 males with testosterone replacement did. Reanalysis of the aggression data comparing the females whose males had no testosterone replacement and females housed with the 6 males that were sexually active also revealed no differences in aggression over the 21-day test period. Since pseudopregnancy is known to last 13 days, these results indicate that the continuous presence of pseudopregnancy is not required for maintenance of aggression by a female cohabiting with a sterile male.
Albert
D J
DJ
Psychology Department, University of British Columbia, Vancouver, Canada.
Jonik
R H
RH
Watson
N V
NV
Moe
I V
IV
Walsh
M L
ML
D000374:Aggression / Q000187:drug effects / Q000523:psychology*; D000818:Animals; D004343:Drug Implants; D005260:Female; D007248:Infertility, Male / Q000523:psychology*; D008297:Male; D009919:Orchiectomy; D010863:Piloerection / Q000502:physiology; D011555:Pseudopregnancy / Q000523:psychology*; D051381:Rats; D012726:Sexual Behavior, Animal / Q000502:physiology; D013739:Testosterone / Q000008:administration & dosage / Q000494:pharmacology
D004343:Drug Implants; D013739:Testosterone