Blanchard R J, Flannelly K J, Blanchard D C
Békésy Laboratory of Neurobiology, University of Hawaii, Honolulu 96822.
Physiol Behav. 1988;43(1):1-7. doi: 10.1016/0031-9384(88)90089-3.
Six mixed-sex colonies of Long-Evans rats were observed at 100-day intervals from colony formation at 100 days of age until all colony members died. Long-term stable dominance relations were observed among males in four colonies while two colonies which had low initial levels of aggression continued to show low intracolony conflict at all ages and no clear dominance relationships. Agonistic interactions among females and between males and females were relatively infrequent and no dominance hierarchy among females was apparent. The aggression of resident males toward intruders increased from 201-601 days of age, but declined overall at age 701. Nevertheless, older males which fought intruders did so as readily as they had when they were young and the few animals that reached 800 days of age continued to attack intruders. Although no systematic decline in total duration or intensity of offense was found across age, there was some evidence of impaired motor performance by older males.
从100日龄形成群体开始，每隔100天对六个长-伊文斯大鼠的混合性别群体进行观察，直至所有群体成员死亡。在四个群体中观察到雄性之间存在长期稳定的优势关系，而另外两个初始攻击水平较低的群体在所有年龄段的群体内部冲突都持续较低，且没有明显的优势关系。雌性之间以及雄性与雌性之间的争斗性互动相对较少，雌性之间没有明显的优势等级制度。常住雄性对入侵者的攻击性在201 - 601日龄时增加，但在701日龄时总体下降。然而，与入侵者争斗的老年雄性和年轻时一样容易，少数活到800日龄的动物仍继续攻击入侵者。尽管未发现攻击的总时长或强度随年龄有系统性下降，但有一些证据表明老年雄性的运动表现受损。
