The Garden Snail is a relatively simple animal that does not have a brain like humans or other chordates have; they have groups of nerve cell bodies (ganglia) connected by nerve cells. They do have a Central and Peripheral Nervous System, meaning they can receive and process stimuli from the environment. These simple creatures are nocturnal and don't have much need for eyesight, but they do have eye-like light sensors which are on the snails upper two tentacles.