two snails on tree trunk - close-up of gastropods on bark

helix aspersa arboreal bark branches brown closeup crawling ecosystem environment forest gastropod mollusks gastropoda gastropods green leaves helicidae pomatia herbivores invertebrates land snails mollusca natural habitat nature outdoors plant eaters pulmonata slimy creatures slow species spiral shells spring summer terrestrial texture tree trunk treeclimbing treedwelling wild wildlife woodland