Flandera V, Nováková V
Dev Psychobiol. 1975 Jan;8(1):49-54. doi: 10.1002/dev.420080107.
Young rats 23 days of age (Wistar strain) that are offspring of aggressive parents will attack mice. They kill them, however, only if the mother has already killed mice in their presence. Rats 30 days of age will kill mice spontaneously without any previous exposure to killing. The occurrence of muricide activity in young rats of this age is the same as in the adult population. If offspring of aggressive parents are reared by nonaggressive foster mothers from birth, they will not exhibit the muricide reaction at 30 days. In adulthood, however, the reaction appears to the same extent as in the offspring of aggressive parents reared by aggressive mothers. If the descendants of nonaggressive parents are reared by aggressive foster mothers from birth, 64.7% of them will kill mice at the age of 30 days. This aggression is retained in equal intensity during adulthood and cannot be attributed to specific learning in that the mothers have never encountered a mouse in the presence of their foster young.
23日龄的幼鼠（Wistar品系）若其父母具有攻击性，那么它们会攻击小鼠。然而，只有在母亲当着它们的面杀死过小鼠的情况下，它们才会杀死小鼠。30日龄的大鼠会自发杀死小鼠，此前无需任何杀戮经历。这个年龄段的幼鼠出现杀鼠行为的情况与成年群体相同。如果具有攻击性的父母的后代从出生起就由无攻击性的养母抚养，那么它们在30日龄时不会表现出杀鼠反应。然而，在成年期，这种反应出现的程度与由具有攻击性的母亲抚养的具有攻击性的父母的后代相同。如果无攻击性的父母的后代从出生起就由具有攻击性的养母抚养，那么其中64.7%的个体在30日龄时会杀死小鼠。这种攻击性在成年期会以相同强度持续存在，且不能归因于特定的学习，因为养母在其抚养的幼崽面前从未接触过小鼠。
