Spruce-fir moss spider

Spruce-fir moss spiders (Microhexura montivaga) are an endangered species of spider found at high elevations in the southern Appalachian Mountains. First identified in 1923, they inhabit moss that grows on rocks underneath the forest canopy. They construct tube-shaped webs, apparently for shelter rather than catching food. The spiders can take as long as three years to reach maturity, due to the low temperatures and resulting slow metabolism.

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The widespread death of Fraser fir trees in the 1980s destroyed many habitats for the spiders, and they were listed as endangered in 1994. Today they are known to exist on Clingmans Dome, Mount Collins, Mount Le Conte, Mount Mitchell, Grandfather Mountain, and Roan Mountain.