SOME DETERMINANTS OF A NATURAL FOOD AVERSION IN NORWAY RATS

Adult male rats were permitted to feed on the carcasses of adult male rodents, freshly sacrificed by CO2 asphyxiation. In a 2-choice preference test, hungry rats were offered 1 conspecific and 1 house mouse, the pair of carcasses being either intact or skinned. Rats [18] that were offered intact carcasses fed on the mouse or on neither carcass, but 18 rats offered skinned carcasses fed indiscriminately, usually on both carcasses. Hungry rats [10], that earlier had observed a cagemate feeding on intact conspecific carcasses, fed more readily on a similar carcass during a single-choice test than did 8 control rats. Rats [20] deprived of food for 96 h fed more readily and consumed more tissue from an intact conspecific carcass than did 20 nondeprived rats. The aversion to feed on the intact carcass of a freshly sacrificed adult conspecific is deprivation dependent and is mediated by chemoreceptive stimuli from the skin and/or fur. The aversion is diminished by social facilitation.