A snail’s mucus can do more than leave a slippery trail. It can lubricate movement, glue the animal to surfaces, fend off predators, and protect it from harsh conditions during dormancy.
By examining secretions from Cepaea nemoralis, researchers have learned how the protein content and calcium chemistry of snail mucus can be tuned to produce materials with distinct properties (Science 2026, DOI: 10.1126/science.adx7367).
C. nemoralis produces five types of snail mucus. Beneath its foot, the snail lays down slippery mucus for movement, while a thin film of adhesive mucus can fasten the rim of the snail’s shell to a surface. When disturbed, the snail releases either a sticky yellow slime or a mass of bubbles. During hibernation, the snail seals itself inside its shell with a mineralized mucus layer called the epiphragm.
All the snail mucus contains water, glycoproteins, and complex carbohydrates. And a combination of proteomics, imaging, and staining techniques revealed collagen VI as a main structural component of the mucus.
“We were very surprised by the proteomics results because of how similar the composition was throughout [these types], although they look and behave completely different,” says Franziska Jehle, a biomaterials researcher at Max Planck Institute of Colloids and Interfaces who led the study.
What differed between the individual mucus materials was the individual and total protein concentration. For example, yellow mucus is roughly 4% protein, compared with about 0.3% for lubricant mucus, and the differences in protein content determine how the materials respond to shear stress.
Calcium provides another means of tuning the mucus. Scanning electron microscopy and spectroscopy revealed tiny granules of amorphous calcium carbonate (ACC), a noncrystalline form of calcium carbonate, packed in the snails’ mucus-secreting glands. In wet mucus, the researchers propose, ACC supplies calcium ions that help cross-link the protein network. Something that previous studies have also noted.
In the epiphragm, however, ACC serves as a precursor to calcite. The researchers even captured images of the granules transitioning into mineral structures. X-ray diffraction confirmed those structures as crystalline calcite.
Aravind Madhyastha, a land-snail researcher at the Ashoka Trust for Research in Ecology and the Environment who was not involved in the study, says that this evolutionary ingenuity behind the epiphragm is “especially significant.” Turning something “soft and slimy into a mineralized barrier that helps the snail survive drought or cold shows that mucus is not merely a by-product of movement but a sophisticated biomaterial,” he says.
Processing further shapes the mucus. Although the two defensive secretions have similar protein compositions, yellow mucus forms a fibrous structure, while collagen gathers around the bubbles in the foam. Jehle says the snail creates the foam by pushing air through its breathing hole during secretion.
“These versatile roles of calcium and collagen VI beautifully exemplify how living organisms optimize the resources at their disposal,” says Ali Miserez, a biological materials researcher at Nanyang Technological University who was not involved in the study. “It’s quite appealing that fine-tuning calcium and other ions identified [in the study] and their interactions with biomolecular components could guide production of materials as different as an adhesive and a lubricant.”
Although snail mucus is used in skin care, the researchers suggest that their findings could be relevant for designing new adhesives, wound dressings or other bioinspired materials.
