Reindeer lichen
A pale, spongy, branching lichen that carpets northern ground. It is a fungus and an alga living as one body, and it is winter food for caribou.
Reindeer lichen at a glance
Cladonia rangiferina RAIN-deer LY-ken; Cladonia rangiferina is kluh-DOH-nee-uh ran-jih-FER-ee-nuh
- Type
- Fungus · lichen
- Diet
- Other
- Size
- Each springy clump grows only ankle-high, about 2 to 4 inches (5 to 10 cm), but a patch can spread across the ground as wide as a bath towel or bigger.
- Lifespan
- It grows very slowly, only about 3 to 5 millimeters a year, so a thick mat can be many decades old.
- Conservation
- Not evaluated (not on the IUCN Red List; common across the far north)
Eats makes its own food (the alga partner uses sunlight)
A reindeer lichen is two living things in one body. A fungus builds the pale, branching frame and soaks up water, while tiny green algae living inside use sunlight to make sugar, the way a leaf does. Working together, they can grow on bare rock and sand where almost no plant can.
Is it safe to touch?
Harmless to touch. It is not poisonous and cannot bite or sting. It is very slow to grow and crunchy when dry, though, so it is easily crushed. Walk around lichen mats instead of on them, and just look.
Reindeer lichen looks like a pale gray-green coral that someone spread across the forest floor: springy, many-branched, ankle-high, soft underfoot when it is wet and crunchy when it is dry. It is one of the strangest living things a person can meet on a trail, because it is not one living thing at all. It is a fungus and a green alga sharing a single body. The fungus builds the branching frame and soaks up water; the algae tucked inside use sunlight to make sugar, the way a leaf does. Together they can live on bare rock and sand where almost nothing else will grow.
That partnership makes reindeer lichen a pioneer. It is often among the first things to cover bare stone after a glacier pulls back or a fire burns through, and as old clumps break down they help make the first thin crumbs of soil for plants that come later. It has no roots and no way to hold water in, so it drinks rain and fog straight through its whole body and simply dries out and waits when the weather turns. All of that happens slowly. A mat grows only a few millimeters a year, which means a thick carpet can be older than the people standing on the trail beside it.
Far north, it becomes food. Caribou and reindeer paw down through deep snow to reach reindeer lichen, and through the hardest part of winter it can make up much of what they eat. It is completely harmless to a person, nothing to bite or sting, nothing poisonous, but it is fragile in the one way that matters. Because it grows so slowly and crushes so easily, a footprint can last for years, so the kind thing is to step around the mats and just look.
Did you know?
- Caribou and reindeer paw through deep snow to reach reindeer lichen, and in winter it can make up much of what they eat.
- It has no roots. It drinks rain and fog straight through its whole body, so it turns crisp and pale when the air is dry and soft again when it is wet.
- It is a slow pioneer. Reindeer lichen is one of the first living things to cover bare rock after a glacier or a fire, and over time it helps build the first thin soil.
Common questions
Is reindeer lichen a plant?
No. It is a fungus and an alga living together as one. That team is called a lichen.
Do reindeer really eat it?
Yes. Caribou and reindeer paw through the snow to eat reindeer lichen all winter.
Can I touch reindeer lichen?
Yes, it is safe. But it grows very slowly and crushes easily, so step around it.
How fast does it grow?
Very slowly, only a few millimeters a year, so a big patch can be many decades old.