The animal that uses sounds as its `eyes` is the bat (option 4). Bats have a unique ability called echolocation, which allows them to navigate and detect objects using sound waves. They emit high-frequency sounds that bounce off objects in their environment, and they listen to the echoes to determine the location, distance, and direction of those objects. This allows bats to effectively "see" in the dark or in dimly lit areas. Dogs (option 1), cats (option 2), and snakes (option 3) do not rely on sound for their primary means of vision. Dogs and cats primarily rely on their eyesight, while snakes have specialized organs, such as infrared-sensitive pits, to detect heat and movement.