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.
Fitzgerald is among the largest and best-known vessels lost on the Great Lakes but she is not alone on the Lake Superior seabed in that area. In the years between 1816, when Invincible was lost, and 1975, when Fitzgerald sank, the Whitefish Point area had claimed at least 240 ships.