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.
The first Victory ship launched in January 1944. In the last years of the war, 414 Victory cargo ships were built, and 117 attack transports. Because the German U-Boat threat had virtually disappeared by 1944, only two Victory ships were sunk by submarines, and three were sunk in the Pacific by Japanese kamikazes.