The Trinity bristle snail (Monadenia setosa) (aka Monadenia infumata setosa in Roth and Sadeghian's "Checklist of the Land Snails and Slugs of California") is a species of medium-sized, air-breathing, land snail

Snail

Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

, a terrestrial

Terrestrial animal

Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...

 pulmonate gastropod mollusc.

This snail is a threatened species

Threatened species

Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...

.

Habitat

This snail is found only in isolated locales along the Trinity River

Trinity River (California)

The Trinity River is the longest tributary of the Klamath River, approximately long, in northwestern California in the United States. It drains an area of the Coast Ranges, including the southern Klamath Mountains, northwest of the Sacramento Valley...

 and nearby small creeks. It can only survive in cool, wet, shady riparian zones.

Life habits

The common name of this species comes from the fact that it has a coating of minuscule bristles on its inch-wide shell. These bristles often pick up bits of plant matter and dirt as the snail moves around, giving the snail a dirty, fuzzy look.

The Trinity bristle snail is dependent on cool, moist conditions and therefore it is only active at night. It spends warmer parts of the day stuck to shady areas on tree trunks, and in especially warm parts of the summer it may not move for days. When conditions are cool enough it feeds on lichen

Lichen

Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...

and the tender parts of green plants. The snail has a lifespan of over ten years, and may not reach full size for nearly that long.

Survival threats

Human encroachment, including logging, mining, and damming, have reduced the snail's habitat to a few patches deep in the forest.