Lichen is a family of small, adaptable fungi that grow symbiotically with various species of algae. The fungi provide survivability and the ability to grow on substrate that might be hostile to algae, while the algae provide photosynthesis to produce food. Hoth cave lichen is a catch all for a number of lichen species that are adapted to the bitterly cold and icy landscape. Different species grow at different cave depths, with more light dependent species growing closer to the cave entrance, while some species can thrive deeper in the lightless depths by absorbing nutrients from predator kills that litter the caves in certain locations. Hoth cave lichen comes in a variety of colours, mostly pale blues and greys, but some species are vibrant yellow or orange and a lilac species was recently discovered. Cave lichen provide sustenance for a number of small herbivores such as voles and lemmings which in turn are preyed on by juvenile wampa and the like.