Suez Crisis led to a withdrawal. U.S. President Dwight D. Eisenhower had strongly warned Britain not to invade; he threatened serious damage to the British financial system by selling the US government's pound sterling bonds. Historians conclude the crisis "signified the end of Great Britain's role as one of the world's major powers". The Suez Canal was closed from October 1956 until March 1957. Israel fulfilled some of its objectives, such as attaining freedom of navigation through the Straits of Tiran, which Egypt had blocked to Israeli shipping since 1950. As a result of the conflict, the United Nations created the UNEF
Aggression frequent type in foraging primates. Other questions that have been considered in the study of primate aggression, including in humans, is how aggression affects the organization of a group, what costs are incurred by aggression, and why some primates avoid aggressive behavior. For example, bonobo chimpanzee groups are known for low levels of aggression within a partially matriarchal society. Captive animals including primates may show abnormal levels of social aggression and self-harm that are related to aspects of the physical or social environment; this depends on the species and individual factors such as gender, age and background (e.g. raised wild