Examine individual changes

'{{copyedit|date=December 2017}} [[file:Erdhörnchen 011.jpg|thumb|230px|[[Cape ground squirrel]].]] A '''fossorial''' (from Latin ''fossor'', "digger") animal is one that is adapted to digging and life underground such as the [[badger]], the [[naked mole-rat]], or the [[mole salamander]]s. Most [[bee]]s and many [[wasp]]s are called "fossorial [[Hymenoptera]]", and a great many [[rodent]]s are considered fossorial although the physical adaptations to living underground are minimal.{{Clarify|reason=vague|date=September 2015}} Nevertheless, mostly from the year 2000 on, for rodents the term ''fossorial'' has been used for species that live in burrows during a considerable part of the day but are surface-dwelling during other parts of the day, while for species that live all their life underground (or at least almost all the time) the term ''subterranean'' has been applied. Some organisms are fossorial to aid in [[temperature regulation]], while others use the underground habitat for protection from [[predator]]s, or for [[food storage]]. An animal is said to be ''sub-fossorial'' if it shows limited adaptations to a fossorial lifestyle.<ref name=":2">Damiani, R, 2003, Earliest evidence of cynodont burrowing, The Royal Society Publishing, Volume 270, Issue 1525</ref> == Prehistoric evidence == The physical adaption of fossoriality was always widespread among many [[Prehistory|prehistoric]] [[Phylum|phyla]] and [[Taxon|taxa]], such as [[bacteria]] and early [[Eukaryote|eukaryotes]], but in the phylum [[Mammal|Mammalia]] this trait has only occurred recently, considering the geological timescale of the earth. The oldest example of a [[cynodont]] (a group of ancient, modern mammals and mammal-like animals) is the [[Thrinaxodon liorhinus]], found in the [[Karoo]] of [[South Africa]] and is estimated to be 251 million years old. Evidence shows that this adaption occurred due to dramatic mass extinctions in the [[Permian]] period.<ref name=":2" /> == Quaternary physical adaptations == [[File:European mole detail of muzzle and paws.jpg|thumb|348x348px| [[European mole|European Mole]] - Note the strong and short forelimbs ]] There are six major external modifications, as described by H.W. Shimer in 1903<ref name=":0" />, that are shared in all mammalian burrowing species: * [[Fusiform]], as an adaption to the dense subsurface environment below earth. * Lesser developed or missing eyesight, considering subsurface darkness. * Small or missing external ears, to reduce natural occurring [[friction]] during burrowing. * Short and stout limbs, since swiftness or speed of movement is less important than the strength to dig. * Broad and stout forelimbs ([[Manus (anatomy)|Manus]]), including long claws, designed to loosen the burrowing material for the hind feet to disperse in the back. * Short or missing tail, which also has little to no [[Locomotive Acts|locomotive]] or burrowing use to most fossorial Mammals.<ref name=":0">Shimer H.W., 1903, Adaptations to aquatic. arboreal, fossorial, and cursorial habits in mammals.III. Fossorial Adaptations, The American Naturalist, Vol.XXXVII, No. 444 - December 1903 </ref> This trait is also argued by Jorge Cubo, as he states that the skull is the main tool during excavation, but that the most active parts are the forelimbs for digging and that the hind-limbs are used for stability.<ref>Cubo, J, 2005, A heterochronic interpretation of the origin of digging adaptions in the northern water vole, Arvicola terrestris (Rodentia: Arvicolidae), Biological Journal of Linnean Society, Volume 87, pages 381-391</ref> Other important physical features include a subsurface adjusted skeleton: a triangular shaped skull, a [[prenasal]] [[Ossicles|ossicle]], chisel shaped teeth, more or less fused and short [[lumbar]] [[Vertebra|vertebrae]], well-developed [[sternum]] and strong forelimb and weaker hind limb bones.<ref name=":0" /> Due to the lack of light, one the most important features of fossorial animals are the development of sensory physical traits that allow them to communicate and navigate in the dark subsurface environment. Considering that sound travels slower in air and faster through solid earth, the use of [[Seismic wave|seismic]] ([[percussive]]) waves on a small scale is more advantageous in these environments. Several different uses are well documented. The cape mole rat [[Cape mole-rat|Georychus capensis]] uses drumming behavior to send messages to its kin through [[conspecific]] signaling. The Namib desert golden mole [[Grant's golden mole|Eremitalpa granti namibensis]] can detect [[termite]] colonies and similar prey underground due to the development of a [[Hypertrophy|hypertrophied]] [[malleus]]. This adaptation allows for better detection of low-frequency signals.<ref>Narins, P.M, 1997, Use of seismic signals by fossorial south African mammals: a neurological goldmine, Brain research bulletin, Vol. 44, Issue 5, pages 641–646</ref> The most likely explanation of the actual transmission of these seismic inputs, captured by the [[Auditory cortex|auditory]] system, is the use of bone conduction; whenever vibrations are applied to the skull, the signals travel through many routes to the inner ear.<ref>Mason, M.J., 2001, Middle ear structures in fossorial mammals: a comparison with non-fossorial species, Journal of Zoology, Vol. 255, Issue 4, Pages 467-486</ref>  == Physiological modifications == One interesting [[Physiology|physiological]] trait, common among many fossorial and semi-fossorial mammals that live in [[Temperate climate|temperate]] zones with partially frozen grounds, is [[hibernation]]. This is due to the seasonal lack of soft succulent [[Herbaceous plant|herbage]] and other sources of nutrition; thus, those species are driven to spend the cold and frozen periods underground.<ref name=":0" /> A conclusion made by W.H. Shimer is that, in general, a species that chose, voluntarily or not, adaptions to the fossorial lifestyle, likely originated as primitive and defenseless [[Rodent|rodents]], [[Insectivore|insectivores]] or [[edentates]] that failed to abundantly find food and protection from predators.<ref name=":0" /> The life underground in these subsurface environments also have direct links to the animal’s [[metabolism]] and [[energetics]]. The weight of the individual specimen here also has direct implications. Animals weighing more than 80 grams have comparably lower basal rates and animals weighing lower than 60 grams have comparably high basal rates, considering species that spend only part of their time burrowing. The average fossorial animal has a [[basal rate]] between 60% and 90%. Further observations conclude that larger burrowing animals, such as [[Hedgehog|hedgehogs]] or [[Armadillo|armadillos,]] have lower thermal conductances than smaller animals, most likely to reduce heat storage in their burrows.<ref>McNab, B, 1979, The Influence of body size on the Energetics and Distribution of Fossorial and Burrowing Mammals, Ecology, Volume 60, pages 1010-1021</ref> == Geological and ecological implications == One important impact on the environment caused by fossorial animals is [[bioturbation]], defined by Marshall Wilkinson as the alteration of fundamental properties of the soil, including surface geomorphic processes.<ref name=":1">Wilkinson, M.T, Richards, P.J., Humphreys, G.S., 2009, Breaking ground: Pedological, geological, and ecological implications of soil bioturbation, Earth Science Reviews, Vol. 97, Issues 1-4, pages 257-272</ref> It is measured that small fossorials, such as [[Ant|ants]], [[Termite|termites]], and [[Earthworm|earthworms]] displace a massive amount of soil. The total global rates displaced by these animals are equivalent to the total global rates of [[tectonic uplift]].<ref name=":1" /> The presence of burrowing animals has also a direct impact on the soils composition, structure and growing vegetation. The impact these animals have can range from feeding, harvesting, caching and soil disturbances, but can differ considering the large diversity of fossorial species - especially [[Herbivore|herbivorous]] species. The net effect is usually composed of an alteration of the composition of plant species and increased plant diversity, which can cause issues with standing crops, as the [[Homogeneity and heterogeneity|homogeneity]] <nowiki/>of the crops are effected.<ref>Huntly, N, Reichman, O.J., 1994, Effects of Subterranean Mammalian Herbivores on Vegetation, Journal of Mammalogy, Volume 75, pages 852-859</ref> Burrowing also impacts the nitrogen cycle in the effected soil. Mounds and bare soils, that contain burrowing animals, have considerably higher amounts of [[Ammonium|NH4]] and [[Nitrate|NO3]] as well as the [[nitrification]] potential and the microbial NO3 consumption than in vegetated soils. The primary mechanism for this occurrence is caused by the removal of the covering grassland.<ref>Canals, H, 2003, How Disturbance by Fossorial Mammals Alters N Cycling in a California Annual Grassland. Ecology, Volume 84, pages 875-881</ref> ==See also== *[[Arboreal]] *[[Burrow]] *[[Cursorial]] *[[Fossa (disambiguation)|Fossa]] ==References== {{Reflist|refs=}} * {{Cite web | title = Fossorial - Definition of Fossorial | publisher = Amateur Entomologists' Society | url = http://www.amentsoc.org/insects/glossary/terms/fossorial | accessdate =1 September 2012 }} * {{Cite web | title = Fossorial Legs | url = http://bugs.bio.usyd.edu.au/learning/resources/Entomology/externalMorphology/imagePages/legs_fossorial.html | publisher = University of Sydney | accessdate =1 September 2012 }} [[Category:Habitats]] [[Category:Cave animals]] {{habitat-stub}}'