They can slide over sharp glass and up walls or plants in this way. The snail's head is actually a part of the foot. Most land snails have two pairs of tentacles, whereas aquatic snails generally have just one pair. Eyes are either at the base or the tips of the upper tentacles. The little eye bulge is quite visible in most land snails.
Vision is poor.
The lower tentacles are usually smaller and are generally used to probe the surface. These provide information regarding smell and touch. The mouth is under the head. The tongue acts like a cheese grater, scraping off bits of food. Snails are primarily herbivores, although some will partake in a meal of a dead animal if the opportunity arises.