Instinctive behavior occurs when an animal has a particular internal state while it is in the presence of a specific external stimulation called a releaser or a sign stimulus.
How many ships did the U-boats sink? During the war the U-boats sank about 2,779 ships for a total of 14.1 million tons GRT. This figure is roughly 70% of all allied shipping losses in all theatres of the war and to all hostile action. The most successful year was 1942 when over 6 million tons of shipping were sunk in the Atlantic.
PT-109 sinks; Lieutenant Kennedy is instrumental in saving crew. On this day in 1943, a Japanese destroyer rams an American PT (patrol torpedo) boat, No. 109, slicing it in two. The destruction is so massive other American PT boats in the area assume the crew is dead. Two crewmen were, in fact, killed, but 11 survived, including Lt. John F. Kennedy. Japanese aircraft had been on a PT boat hunt in the Solomon Islands, bombing the PT base at Rendova Island.