2. Pigs : When it comes to domesticated animals pigs may be the smartest animals known. A experiment conducted the 1990’s first discovered signs of their intelligence. Pigs were trained to move a cursor on a screen using their snouts, and used the cursor to differentiate between symbols they recognised and ones they had seen for the first time. Pigs also have fascinating social lives. Female pigs will actually sing to their children to help calm them down. Pigs get along with each other really well, and can actually communicate with each other through different noises. Pigs know to leave excrement away from their homes, and have trouble getting lost when they leave home.