TY - JOUR A1 - Tinbergen, Niko T1 - The Shell Menace T2 - Th. E. McGill (Ed.), Readings in Animal Behavior, New York etc. (Holt, Rinehart and Winston) 1965, pp. 532-541. Y1 - 1965 UR - https://opus4.kobv.de/opus4-Fromm/frontdoor/index/index/docId/21903 ER -