The shell of a giant ramshorn snail, or Marisa cornuarietis, resembles a ram's horn and is light brown. Ramshorn snails are native to Central and South America, but were introduced to South Florida's canals. While the source of their introduction is not known, the Florida Department of Environmental Protection, or FDEP, speculates they were released from an aquarium in a South Florida residence. The FDEP also believes the invasion of giant ramshorn snails may one day negatively impact Florida's environment because ramshorn snails compete with native land snails for food and shelter.
There are two land snails in Florida that prey on other snails. According to the University of Florida, the most common predatory snail in the Sunshine State is the rosy predator snail, or Euglandina rosa. The rosy predator has a long, rose-colored shell and is found in hardwood forests and home gardens. Rosy predator snails were used by the Florida government to eliminate giant African snails, which invaded Florida during the 1960s and 1970s. The decollate snail, or Rumina decollata, has a spiraling brown shell and is native to the Mediterranean. In Florida, the decollate land snail can be found near Miami, Pensacola and Marathon. Floridian agriculturists introduced decollate snails to the Sunshine State in the 20th century to prey on garden pests, notably brown garden snails.
The Florida apple snail, or Pomacea paludosa, is a common sight in marshes and swamps throughout the state. Apple snails are named because their shells resemble apples. They spend most of their time on emergent vegetation in aquatic habitats. During the summer, many of Florida's marshes experience a "dry down" period -- lower water levels. Apple snails aestivate, or hibernate, during these dry periods.
According to the University of Florida, there are two common garden snails in the state -- the garden zachrysia and the banded caracol. Both snails, originally found in Cuba, were introduced to South Florida in the early 20th century. Garden zachrysias, or Zachrysia provisia, feast on small fruits and ornamental plants, while banded caracols, or Caracolus marginellus, eat algae and decaying plants. Banded caracols have shells that are 1 1/2 inches long. Garden zachrysia shells are approximately 1 inch long.