A mineral lick (also known as salt lick or natural lick) is a natural mineral deposit where animals in nutrient-poor ecosystems can obtain essential mineral nutrients. In an ecosystem, salt/mineral licks often occur naturally, providing the sodium, calcium, iron, phosphorus and zinc required in the springtime for bone, muscle and other growth in deer and other wildlife, such as moose, elephants, cattle, woodchucks, domestic sheep, fox squirrels, mountain goats and porcupines. Harsh weather exposes salty mineral deposits that draw animals from miles away for a taste of needed nutrients. It is thought that certain fauna can detect calcium in salt licks.
Many animals regularly visit mineral licks to consume clay, supplementing their diet with nutrients and minerals. Some animals require the minerals at these sites not for nutrition, but to ward off the effects of secondary compounds that are included in the arsenal of plant defences against herbivory. The mineral contents of these sites usually contain calcium (Ca), magnesium (Mg), sulfur (S) phosphorus (P), potassium (K), and sodium (Na). Mineral lick sites play a critical role in the ecology and diversity of organisms that visit these sites, however, little is still understood about the dietary benefits. "The adjectives ‘mineral’ and ‘salt’ bear witness to the common proposition, in the ecological literature, that animals eat soil to satisfy a craving for nutrient minerals, resulting from inadequate forage. However, for wild animals which frequent licks, sodium (Na) is the only mineral identified so far, with strong evidence that an extra supply is indeed needed and sought in some cases.":107 Nonetheless, many studies have identified other uses and nutritional benefits from other micronutrients that exist at these sites, including Selenium (Se), Cobalt (Co) and/or Molybdenum (Mo). In addition to the utilization of mineral licks, many animals suffer from traffic collisions as they gather to lick salts accumulated on road surfaces. Animals also consume dirt (geophagy) to obtain minerals, such as Canadian moose mining for minerals from the root wads of fallen trees.
- Mills, A.; Milewski, A. (2007). "Geophagy and nutrient supplementation in the Ngorongoro Conservation Area, Tanzania, with particular reference to selenium, cobalt and molybdenum". Journal of Zoology 271 (1): 110–118. doi:10.1111/j.1469-7998.2006.00241.x.
- Ayotte, J. B.; Parker, K. L.; Arocena, J. M.; Gillingham, M. P. (2006). "Chemical composition of lick soils: Functions of soil ingestion by four ungulate species". Journal of Mammalogy 87 (5): 878–888. doi:10.1644/06-MAMM-A-055R1.1.
- Rea, R. "Mining and geophagy of root wad soils by moose in winter". Wildlife Afield 4 (1): 86–87.
- Klassen, N. A.; Rea, R. V. (2008). "What do we know about nocturnal activity of moose?". Alces 44: 101–109.
- Prose Edda by Snorri Sturluson