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 Axis diverted their forces to the Battle of Tunisia, and attacks on Malta were rapidly reduced. The siege effectively ended in November 1942. In December 1942, air and sea forces operating from Malta went over to the offensive. By May 1943, they had sunk 230 Axis ships in 164 days, the highest Allied sinking rate of the war. The Allied victory in Malta played a major role in the eventual Allied success in North Africa.