Reindeer are herbivores that consume most of their diet by grazing, and eat up to 12 pounds of food a day.  In the winter months, 90% of the reindeer's diet is constituted of  lichens, specifically Cladonia rangiferina (reindeer lichen) .  Other species such as C. arbuscula (shrubby or tree reindeer lichen), C. mitis (green or yellow reindeer lichen), and C. stellaris (star or star-tippedA typical reindeer lichen.  Volk, T. 2002. (image)

 reindeer lichen) are also all consumed by reindeer. The reindeer are essentially dependent upon them for survival. Lichens are mutualistic combinations of a fungus and either an alga or cyanobacteria, and are able to thrive in harsh conditions by growing close to the ground in thick colonies on nearly bare rock, or in a thin layer of soil.  Reindeer uncover the snow-covered lichens by kicking holes in the ice and snow to expose them.  Learn more about other reindeer adaptations here.  This “cratering” technique gives them a competitive advantage over other herbivores of the area who can only rely on boreal lichens.  Lichens are rich in carbohydrates and low in protein content; reindeer are able to break down carbohydrates, fiber, and metabolize nitrogen by mutualistic bacteria in the rumen portion of their four-chambered stomach.  Because lichens are lacking in protein, they also consume other protein-rich foods such as lemmings, bird eggs, and mushrooms to make up for it.12 

            Cladonia cornus lichen in Alaska. Volk, T. 2002. "cladonia cornus AK tjv." (image)


To learn more about reindeer lichens, check out this great site on Cladonia rangifera!

In the summer months they consume leaves of willows and birches, roots andAmantia muscaria, a hallucinogenic mushroom that is a favorite of reindeer.  Volk, T. 1999."Amanita Muscaria." (image) <>. Accessed 9 April 2009.

tubers, wood/bark and stems, mushrooms as stated above, cotton grass, mosses, blueberry bushes, sedges, bryophytes, and other types of ground vegetation.  Reindeer possess small, weak teeth, and spend a large portion of their time chewing.10  In reference to mushrooms, reindeer especially love the hallucinogenic mushroom Amantia muscaria.  To learn more about the reindeer's appetite for these intoxicating and hallucinogenic mushrooms, and how it may have also contributed to the legend of Santa Claus and his flying reindeer, check out this interesting video!

                       Moss, a common food of reindeer.  Mudde, D. 2007. "Mos." (image). <>. Accessed 9 April 2009. 


Reindeer store their food as fat, which they use as a reserve in the winter months to conserve energy when food is scarce.  Because they are ruminants, they possess a four-chambered stomach for digestion of food.  The reticulum, rumen, and omasum are the primary compartments for digestion before food enters the stomach (abomasum).  These compartments allow the reindeer to digest vegetation that humans cannot. The reticulum collects foreign objects and also moves ingested food into the subsequent compartments.  The rumen is the large "fermentation vat" that contains millions of bacteria.  These bacteria secrete enzymes that have the ability to degrade cellulose.  The rumen also absorbs fatty acid by-products of digestion.  The omasum helps to grind food, and also removes liquid from ingested roughage. Lastly, the abomasum is the site of gastric secretion that digests food and specifically carbohydrates, and it contains a low pH that breaks down protein and kills any bacteria that may be present.18 


Learn about the life history of reindeer from young to old next!



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