Editing Antler

{{Short description|Extensions of the skull found in animals of the family Cervidae (deer)}}
{{About|the antlers of deer and related species}}
{{Use mdy dates|date=June 2021}}
[[File:Red deer stag 2009 denmark.jpg|thumb|upright|right|Mature [[red deer]] stag, Denmark]]
[[File:Antlers at the start of the season, cervus elaphus, deinze, belgium.jpg|thumb|upright|Red deer at the beginning of the growing season]]
   
'''Antlers''' are extensions of an animal's [[skull]] found in members of the [[Cervidae]] (deer) [[Family (biology)|family]]. Antlers are a single structure composed of [[bone]], [[cartilage]], [[fibrous tissue]], [[skin]], [[nerve]]s, and [[blood vessel]]s. They are generally found only on males, with the exception of [[Reindeer|reindeer/caribou]].<ref>{{cite web|url=https://naturalhistory.si.edu/arctic/html/caribou_reindeer.html|title=Arctic Wildlife – Arctic Studies Center|website=naturalhistory.si.edu|access-date=May 1, 2018|url-status=dead|archive-url=https://web.archive.org/web/20180501003502/https://naturalhistory.si.edu/arctic/html/caribou_reindeer.html|archive-date=May 1, 2018}}</ref> Antlers are [[Moulting|shed and regrown]] each year and function primarily as objects of [[sexual attraction]] and as [[Weapon (biology)|weapons]].<ref>{{Cite web |date=2019-01-14 |title=What are antlers and what is their purpose? |url=https://aceantlers.com/blogs/news/what-are-deer-antlers |access-date=2023-06-21 |website=Ace Antlers |language=en}}</ref>

==Etymology==
Antler comes from the [[Old French]] ''antoillier ''(see present French : "Andouiller", from'' ant-, ''meaning before,'' oeil, ''meaning eye and'' -ier'', a suffix indicating an action or state of being)<ref>{{Cite book | last1 = Brown | first1 = Leslie | year = 1993 | title = The New Shorter Oxford English Dictionary, Volume 1 | publisher = Clarendon Press | isbn = 0-19-861271-0 | url-access = registration | url = https://archive.org/details/newshorteroxford00lesl }}</ref><ref name=Harper>{{cite encyclopedia | last1 = Harper | first1 = Douglas | year = 2010 | title = Online Etymology Dictionary | dictionary = Dictionary.com | url = http://dictionary.reference.com/browse/antler | access-date = November 8, 2010| archive-url= https://web.archive.org/web/20101108133938/http://dictionary.reference.com/browse/antler| archive-date= November 8, 2010 | url-status= live}}</ref> possibly from some form of an unattested Latin word ''*anteocularis'', "before the eye"<ref>{{cite web |url=http://www.collinsdictionary.com/dictionary/english/antler |title=antler |work=CollinsDictionary.com. Collins English Dictionary – Complete & Unabridged 11th Edition. Retrieved October 27, 2012 |url-status=live |archive-url=https://web.archive.org/web/20121028191800/http://www.collinsdictionary.com/dictionary/english/antler |archive-date=October 28, 2012 }}</ref> (and applied to the word for "branch" or "[[horn (anatomy)|horn]]"<ref name=Harper/>).

== Structure and development ==
[[File:KaempfendeHirsche-2-cropped.jpg|thumb|right|Male [[fallow deer]] fighting]]
[[File:Sambar deers Fighting Silvassa.jpg|right|thumb|Two sambar deer fighting, [[Silvassa]], India]]Antlers are unique to [[cervid]]s. The ancestors of deer had [[tusk]]s (long upper [[canine tooth|canine teeth]]). In most species, antlers appear to replace tusks. However, one modern species (the [[water deer]]) has tusks and no antlers and the [[muntjac]]s have small antlers and tusks. The [[musk deer]], which are not true cervids, also bear tusks in place of antlers.<ref name=Hall/>

In contrast to antlers, [[horn (anatomy)|horn]]s—found on [[pronghorn]]s and [[Bovidae|bovids]], such as sheep, goats, bison and cattle—are two-part structures that usually do not shed. A horn's interior of bone is covered by an exterior sheath made of [[keratin]]<ref>{{Cite web |last=Love |first=Heather |title=What Is The Difference Between Horns And Antlers? |url=https://indianapublicmedia.org/amomentofscience/horns-versus-antlers.php |access-date=December 5, 2020 |website=A Moment of Science – Indiana Public Media}}</ref> (the same material as human [[fingernails]] and toenails).

Antlers are usually found only on males. Only reindeer (known as caribou in North America) have antlers on the females, and these are normally smaller than those of the males. Nevertheless, fertile [[wiktionary:doe#English|does]] from other species of deer have the capacity to produce antlers on occasion, usually due to increased testosterone levels.<ref>[http://www.das.psu.edu/research-extension/deer/photos/antlered-doe Antlered Doe] {{webarchive |url=https://web.archive.org/web/20120229040529/http://www.das.psu.edu/research-extension/deer/photos/antlered-doe |date=February 29, 2012 }}</ref> The "horns" of a [[pronghorn]] (which is not a cervid but a [[Antilocapridae|antilocaprid]]) meet some of the criteria of antlers, but are not considered true antlers because they contain [[keratin]].<ref>{{cite web|url=http://www.sandiegozoo.org/animalbytes/t-pronghorn%7C|title=Mammals: Pronghorn
|publisher=San Diego Zoo|access-date=June 27, 2013}}
</ref>
[[File:Red deer stag velvet.jpg|thumb|upright|An antler on a red deer stag. Velvet covers a growing antler, providing blood flow that supplies oxygen and nutrients.]]

Each antler grows from an attachment point on the skull called a pedicle. While an antler is growing, it is covered with highly [[Blood vessel|vascular]] skin called [[Velvet antler|velvet]], which supplies oxygen and nutrients to the growing bone.<ref name=Hall>{{Cite book | last = Hall | first = Brian K. | year = 2005 | title = Bones and Cartilage: Developmental and Evolutionary Skeletal Biology | publisher = Academic Press | chapter = Antlers | pages = 103–114 | isbn = 0-12-319060-6 | chapter-url = https://books.google.com/books?id=y-RWPGDONlIC&pg=PA103 | access-date = November 8, 2010 }}</ref> Antlers are considered one of the most exaggerated cases of male secondary sexual traits in the animal kingdom,<ref name="Malo">{{cite journal |doi=10.1098/rspb.2004.2933 |pmid=15695205 |pmc=1634960 |title=Antlers honestly advertise sperm production and quality |journal=Proceedings of the Royal Society B: Biological Sciences |volume=272 |issue=1559 |pages=149–57 |year=2005 |last1=Malo |first1=A. F. |last2=Roldan |first2=E. R. S. |last3=Garde |first3=J. |last4=Soler |first4=A. J. |last5=Gomendio |first5=M. }}</ref> and grow faster than any other mammal bone.<ref name=W&H>{{Cite book | last1 = Whitaker | first1 = John O. | last2 = Hamilton | first2 = William J. Jr. | year = 1998 | title = Mammals of the Eastern United States | publisher = Cornell University Press | page = 517 | isbn = 0-8014-3475-0 | url = https://books.google.com/books?id=5fVymWAez-YC&pg=PA517 | access-date = November 8, 2010 }}</ref> Growth occurs at the tip, and is initially [[cartilage]], which is later replaced by bone tissue. Once the antler has achieved its full size, the velvet is lost and the antler's bone dies. This dead bone structure is the mature antler. In most cases, the bone at the base is destroyed by [[osteoclast]]s and the antlers fall off at some point.<ref name=Hall/> As a result of their fast growth rate, antlers are considered a handicap since there is an immense nutritional demand on deer to re-grow antlers annually, and thus can be [[Signalling theory|honest signals]] of metabolic efficiency and food gathering capability.<ref name="Ditchkoff">{{cite journal |doi=10.1111/j.0014-3820.2001.tb00794.x |pmid=11327168 |title=Major-Histocompatibility-Complex-Associated Variation in Secondary Sexual Traits of White-Tailed Deer (Odocoileus Virginianus): Evidence for Good-Genes Advertisement |journal=Evolution |volume=55 |issue=3 |pages=616–25 |year=2007 |last1=Ditchkoff |first1=Stephen S. |last2=Lochmiller |first2=Robert L. |last3=Masters |first3=Ronald E. |last4=Hoofer |first4=Steven R. |last5=Bussche |first5=Ronald A. Van Den |s2cid=10418779 |doi-access=free }}</ref>
[[File:Geweihe Pierer.jpg|thumb|right|upright|Increasing size of antlers year on year in different European game species, 1891 illustration]]

In most Arctic and temperate-zone species, antler growth and shedding is annual, and is controlled by the length of daylight.<ref name="doi.org">{{Cite journal |last1=Rössner |first1=Gertrud E. |last2=Costeur |first2=Loïc |last3=Scheyer |first3=Torsten M. |date=2020-12-16 |title=Antiquity and fundamental processes of the antler cycle in Cervidae (Mammalia) |url=https://doi.org/10.1007/s00114-020-01713-x |journal=The Science of Nature |language=en |volume=108 |issue=1 |pages=3 |doi=10.1007/s00114-020-01713-x |issn=1432-1904 |pmc=7744388 |pmid=33326046}}</ref> Although the antlers are regrown each year, their size varies with the age of the animal in many species, increasing annually over several years before reaching maximum size. In tropical species, antlers may be shed at any time of year, and in some species such as the [[sambar (deer)|sambar]], antlers are shed at different times in the year depending on multiple factors. Some equatorial deer never shed their antlers.{{citation needed|date=November 2023}}

A 2019 study published in ''[[Science (journal)|Science]]'' identified eight genes active in antler formation that are normally associated with [[bone cancer]], particularly [[osteosarcoma]]. Additional tumor-suppressing and tumor-growth-inhibiting genes were determined to be responsible for regulating antler growth. This was taken to indicate that antler formation is more similar to a highly controlled form of cancer growth than to normal bone development.<ref>{{cite magazine |last= Pennisi |first= Elizabeth |date= 20 Jun 2019 |title= Cancer genes help deer antlers grow |url= https://www.science.org/content/article/cancer-genes-help-deer-antlers-grow |magazine= Science |publisher= American Association for the Advancement of Science |access-date= 4 November 2023}}</ref>

Antlers function as both weapons in male-male competition and as displays of sexual ornaments for females.<ref name="W&H" /><ref>{{Cite journal |last1=Morina |first1=Daniel L. |last2=Demarais |first2=Steve |last3=Strickland |first3=Bronson K. |last4=Larson |first4=Jamie E. |date=2018-04-01 |title=While males fight, females choose: male phenotypic quality informs female mate choice in mammals |journal=Animal Behaviour |language=en |volume=138 |pages=69–74 |doi=10.1016/j.anbehav.2018.02.004 |s2cid=3942922 |issn=0003-3472|doi-access=free }}</ref> Because mature antlers are no longer living during combat, antler fractures are incapable of being repaired following competition. A study in 2019 hypothesized that the periodic casting and regrowth of antlers might have evolved as a way to ensure the availability of complete antler sets to display each year.<ref>{{Cite journal |last1=Landete-Castillejos |first1=T. |last2=Kierdorf |first2=H. |last3=Gomez |first3=S. |last4=Luna |first4=S. |last5=García |first5=A. J. |last6=Cappelli |first6=J. |last7=Pérez-Serrano |first7=M. |last8=Pérez-Barbería |first8=J. |last9=Gallego |first9=L. |last10=Kierdorf |first10=U. |date=2019 |title=Antlers - Evolution, development, structure, composition, and biomechanics of an outstanding type of bone |url=https://pubmed.ncbi.nlm.nih.gov/31446115/ |journal=Bone |volume=128 |pages=115046 |doi=10.1016/j.bone.2019.115046 |issn=1873-2763 |pmid=31446115|hdl=10578/30778 |s2cid=201751091 |hdl-access=free }}</ref> Antler regeneration in male deer ensures that every mating season begins on a clean slate, as an increase in branching size and complexity happens each regeneration cycle in an individual.<ref name="doi.org"/>

== Mechanical properties ==
[[Bone|Bones]] typically serve a structural purpose, with load bearing abilities that are greater than any other part of an animal's body. Bones typically differ in shape and properties to better fit their overall function. <ref name=":1">{{Cite journal |last1=Landete-Castillejos |first1=T. |last2=Currey |first2=J. D. |last3=Estevez |first3=J. A. |last4=Gaspar-López |first4=E. |last5=Garcia |first5=A. |last6=Gallego |first6=L. |date=November 2007 |title=Influence of physiological effort of growth and chemical composition on antler bone mechanical properties |url=https://www.sciencedirect.com/science/article/pii/S8756328207005662 |journal=Bone |volume=41 |issue=5 |pages=794–803 |doi=10.1016/j.bone.2007.07.013 |pmid=17822969 |via=Elsevier Science Direct}}</ref> Antlers are not structural and typically have different properties when compared to structural bones like femurs.

While antlers are classified as bone, they differ in some ways from human bones and [[Bovinae|bovine]] bones. Bone is characterized as being made up of primarily [[collagen]] and a [[Hydroxyapatite|mineral phase]].<ref>{{Cite journal |last1=Chen |first1=Poyu |last2=Stokes |first2=A. G. |last3=McKittrick |first3=Joanna M. |date=February 2009 |title=Comparison of the structure and mechanical properties of bovine femur bone and antler of the North American elk (Cervus elaphus canadensis) |url=https://www.sciencedirect.com/science/article/pii/S1742706108002857 |journal=Acta Biomaterialia |volume=5 |issue=2 |pages=693–706 |doi=10.1016/j.actbio.2008.09.011 |pmid=18951859 |via=Elsevier Science Direct}}</ref> In antlers, the mineral content is considerably lower than other examples of bone tissue, while having a high volume of collagen.<ref>{{Cite journal |last1=Picavet |first1=P. P. |last2=Balligand |first2=M. |date=12 September 2016 |title=Organic and mechanical properties of Cervidae antlers: a review |url=https://link.springer.com/article/10.1007/s11259-016-9663-8#auth-P__P_-Picavet-Aff1 |journal=Veterinary Research Communications |volume=40 |issue=3–4 |pages=141–147 |doi=10.1007/s11259-016-9663-8 |pmid=27618827 |via=Springer Link}}</ref> This leads antlers to having lower [[Yield (engineering)|yield strength]] and [[stiffness]], but higher [[fracture toughness]] when compared to human cortical bone. Mineral content differs among species and also depends on the food availability. <ref name=":1" /> In recent studies, increase in mineral content has been linked to the increase in stiffness with a decrease in fracture toughness. <ref name=":2">{{Cite journal |last1=Fang |first1=Zhongqi |last2=Chen |first2=Bin |last3=Lin |first3=Shiyun |last4=Ye |first4=Wei |last5=Xiao |first5=Hang |last6=Chen |first6=Xi |date=December 2018 |title=Investigation of inner mechanism of anisotropic mechanical property of antler bone |url=https://www.sciencedirect.com/science/article/pii/S1751616118302467 |journal=Journal of the Mechanical Behavior of Biomedical Materials |volume=88 |pages=1–10 |doi=10.1016/j.jmbbm.2018.07.043 |pmid=30114597 |via=Elsevier Science Direct}}</ref>

Further, bones are highly [[Anisotropy|anisotropic]] due to their hierarchical structure. Thus, mechanical properties are highly dependent on testing conditions and directions. <ref name=":2" /> Due to their cylindrical shape, antlers can be tested using bending along three different [[Cylinder stress|orientations]]. [[Four-point flexural test|Bend testing]] in these orientations have resulted in different mechanical properties. In samples from antler bone taken in the transverse direction, an [[elastic modulus]] of 8.92–10.02 [[Pascal (unit)|GPa]] was reported. For the longitudinal and radial orientations, the elastic modulus was 7.19–8.23 and 4.01–4.27 GPa respectively. <ref name=":2" /> The transverse direction was overall found to be the stronger orientation with higher mechanical properties. The ultimate tensile strength of 262.96–274.38 MPa in the transverse direction was statistically significant when compared to the longitudinal and radial directions' values of 46.91–48.55 and 41.75–43.67 MPa. <ref name=":2" />

[[Tensile testing]] of antler bones has also been conducted to compare to bovine femur results. The antler samples were tested in dry and wet conditions as done in other studies. The wetness of a sample resulted in a difference in mean maximum [[Strain (mechanics)|strain]]: 1.46% and 2.2%, dry and wet respectively. Further, the ultimate tensile strength of wet, dry and bovine difference showed differences as well: 188 MPa, 108 MPa, and 99.2 MPa for dry, wet and bovine samples respectively. Similarly, the elastic modulus for dry samples was 17.1 GPa, 7.5 GPa for wet samples, and 17.7 GPa for bovine femur. <ref>{{Cite journal |last1=Rajaram |first1=A. |last2=Ramanathan |first2=N. |date=December 1982 |title=Tensile properties of antler bone |url=https://link.springer.com/article/10.1007/BF02411255 |journal=Calcified Tissue International |volume=34 |issue=3 |pages=301–305 |doi=10.1007/BF02411255 |pmid=6809293 |via=Springer Link}}</ref> This difference in elastic modulus is due to the difference in function of a bovine femur versus an antler. Bovine femurs must withstand greater stresses, holding up the body of the animal, whereas an antler is used for sexual selection and competition.

==Function==
=== Sexual selection ===
The principal means of evolution of antlers is sexual selection, which operates via two mechanisms: male-to-male competition (behaviorally, physiologically) and female [[mate choice]].<ref name="Malo"/> Male-male competition can take place in two forms. First, they can compete behaviorally where males use their antlers as weapons to compete for access to mates; second, they can compete physiologically where males present their antlers to display their strength and fertility competitiveness to compete for access to mates.<ref name="Malo"/> Males with the largest antlers are more likely to obtain mates and achieve the highest fertilization success due to their competitiveness, dominance and high phenotypic quality.<ref name="Malo"/> Whether this is a result of male-male fighting or display, or of female choosiness differs depending on the species as the shape, size, and function of antlers vary between species.<ref name="Gilbert"/>

=== Heritability and reproductive advantage ===
There is evidence to support that antler size influences mate selection in the red deer, and has a heritable component.  Despite this, a 30-year study showed no shift in the median size of antlers in a population of red deer.<ref name="Kruuk">{{cite journal|last1=Kruuk|first1=Loeske E. B.|author-link=Loeske Kruuk|last2=Slate|first2=Jon|last3=Pemberton|first3=Josephine M.|last4=Brotherstone|first4=Sue|last5=Guinness|first5=Fiona|last6=Clutton-Brock|first6=Tim|year=2002|title=Antler Size in Red Deer: Heritability and Selection but No Evolution|url=https://www.researchgate.net/publication/11103156|url-status=live|journal=Evolution|volume=56|issue=8|pages=1683–95|doi=10.1111/j.0014-3820.2002.tb01480.x|pmid=12353761|archive-url=https://web.archive.org/web/20160916134423/https://www.researchgate.net/profile/Loeske_Kruuk/publication/11103156_Antler_size_in_red_deer_heritability_and_selection_but_no_evolution/links/54478d6b0cf22b3c14e0ea12.pdf|archive-date=September 16, 2016|via=|s2cid=33699313}}</ref> The lack of response could be explained by environmental covariance, meaning that lifetime breeding success is determined by an unmeasured trait which is phenotypically correlated with antler size but for which there is no [[genetic correlation]] of antler growth.<ref name="Kruuk"/> Alternatively, the lack of response could be explained by the relationship between heterozygosity and antler size, which states that males heterozygous at multiple loci, including MHC loci, have larger antlers.<ref name="Gonzalez">{{cite journal |doi=10.1093/jhered/esq049 |pmid=20478822 |title=Low Heterozygosity at Microsatellite Markers in Iberian Red Deer with Small Antlers |journal=Journal of Heredity |volume=101 |issue=5 |pages=553–61 |year=2010 |last1=Perez-Gonzalez |first1=J. |last2=Carranza |first2=J. |last3=Torres-Porras |first3=J. |last4=Fernandez-Garcia |first4=J. L. |doi-access=free }}</ref> The evolutionary response of traits that depend on heterozygosity is slower than traits that are dependent on additive genetic components and thus the evolutionary change is slower than expected.<ref name="Gonzalez"/> A third possibility is that the costs of having larger antlers (resource use, and mobility detriments, for instance) exert enough selective pressure to offset the benefit of attracting mates; thereby stabilizing antler size in the population.

===Protection against predation===

If antlers functioned only in male–male competition for mates, the best evolutionary strategy would be to shed them immediately after the rutting season, both to free the male from a heavy encumbrance and to give him more time to regrow a larger new pair. Yet antlers are commonly retained through the winter and into the spring,<ref name=wolves>{{cite journal |title=Predation shapes the evolutionary traits of cervid weapons |journal=Nature Ecology & Evolution |date=September 3, 2018 |last1=Metz |first1=Matthew C. |last2=Emlen |first2=Douglas J. |last3=Stahler |first3=Daniel R. |last4=MacNulty |first4=Daniel R. |last5=Smith |first5=Douglas W. |volume=2 |issue=10 |pages=1619–1625 |doi=10.1038/s41559-018-0657-5 |pmid=30177803 |bibcode=2018NatEE...2.1619M |s2cid=52147419 }}</ref> suggesting that they have another use. [[wolf|Wolves]] in [[Yellowstone National Park]] are 3.6 times more likely to attack individual male [[elk]] without antlers, or groups of elk in which at least one male is without antlers.<ref name=wolves /> Half of all male elk killed by wolves lack antlers, at times in which only one quarter of all males have shed antlers. These findings suggest that antlers have a secondary function in deterring predation.

=== Female antlers in reindeer ===
[[Image:20070818-0001-strolling reindeer.jpg|thumb|Reindeer in Kebnekaise valley, [[Sweden]]]]
[[Reindeer]] (''Rangifer tarandus)'' are the only cervid species that inhabit the Arctic and subarctic regions of the globe, yet their most striking distinction is the presence of pedicles after birth and antlers in both males and females.<ref>{{Cite journal |last=Nasoori |first=Alireza |date=2020 |title=Formation, structure, and function of extra-skeletal bones in mammals |url=https://onlinelibrary.wiley.com/doi/10.1111/brv.12597 |journal=Biological Reviews |language=en |volume=95 |issue=4 |pages=986–1019 |doi=10.1111/brv.12597 |pmid=32338826 |s2cid=216556342 |issn=1464-7931}}</ref><ref>{{Cite journal |last1=Lin |first1=Zeshan |last2=Chen |first2=Lei |last3=Chen |first3=Xianqing |last4=Zhong |first4=Yingbin |last5=Yang |first5=Yue |last6=Xia |first6=Wenhao |last7=Liu |first7=Chang |last8=Zhu |first8=Wenbo |last9=Wang |first9=Han |last10=Yan |first10=Biyao |last11=Yang |first11=Yifeng |last12=Liu |first12=Xing |last13=Sternang Kvie |first13=Kjersti |last14=Røed |first14=Knut Håkon |last15=Wang |first15=Kun |date=2019-06-21 |title=Biological adaptations in the Arctic cervid, the reindeer ( Rangifer tarandus ) |journal=Science |language=en |volume=364 |issue=6446 |pages=eaav6312 |doi=10.1126/science.aav6312 |pmid=31221829 |bibcode=2019Sci...364.6312L |s2cid=195191761 |issn=0036-8075|doi-access=free }}</ref> One possible reason that females of this species evolved antlers is to clear away snow so they can eat the vegetation underneath.<ref name=Hall/> Another possible reason is for female competition during winter foraging.<ref name="Gilbert"/> Espmark (1964) observed that the presence of antlers on females is related to the hierarchy rank and is a result of the harsh winter conditions and the female dominated parental investment.<ref>{{Cite journal |last=Espmark |first=Yngve |date=1964-10-01 |title=Studies in dominance-subordination relationship in a group of semi-domestic reindeer (Rangifer tarandus L.) |url=https://dx.doi.org/10.1016/0003-3472%2864%2990061-2 |journal=Animal Behaviour |language=en |volume=12 |issue=4 |pages=420–426 |doi=10.1016/0003-3472(64)90061-2 |issn=0003-3472}}</ref> Males shed their antlers prior to winter, while female antlers are retained throughout winter.<ref>{{cite journal|date=December 2001|title=Antlers on Female Caribou: Biogeography of the Bones of Contention|jstor=2680172|journal=Ecology|volume=82|issue=12|pages=3556–3560|last1=Schaefer and Mahoney|doi=10.2307/2680172}}</ref> Also, female antler size plateaus at the onset of puberty, around age three, while males' antler size increases during their lifetime.<ref name="Melnycky"/> This likely reflects the differing life history strategies of the two sexes, where females are resource limited in their reproduction and cannot afford costly antlers, while male reproductive success depends on the size of their antlers because they are under directional sexual selection.<ref name="Melnycky">{{cite journal|last1=Melnycky|display-authors=et al|title=Scaling of antler size in reindeer (Rangifer tarandus): sexual dimorphism and variability in resource allocation|journal=Journal of Mammalogy|date=December 2013|volume=94|issue=6|pages=1371–1379|doi=10.1644/12-mamm-a-282.1|s2cid=86047535|doi-access=}}</ref> In other species of deer, the presence of antlers in females indicates some degree of [[intersex]] condition, the frequency of which has been seen to vary from 1.5%<ref>{{Cite journal |last=Wishart |first=William |date=1985 |title=Frequency of Antlered White-Tailed Does in Camp Wainwright, Alberta
|journal=Journal of Wildlife Management|volume=49|issue=2|pages=386–388|doi=10.2307/3801538 |jstor=3801538}}</ref> to 0.02%.<ref>{{cite journal |last1=Donaldson|first1=John|last2=Doutt|first2=J. Kenneth|jstor=3798545|title=Antlers in Female White-Tailed Deer: A 4-Year Study|journal=Journal of Wildlife Management|date=1965 |volume=29|issue=4|pages=699–705|doi=10.2307/3798545 }}</ref>

=== Antenna for hearing===
[[Image:Luchik-the-Moose-and-Dr-Minaev-hp3188.jpg|thumb|A six-year old moose undergoing domestication at [[Kostroma Moose Farm]]<ref>{{cite web|url=http://www.moose-farm.ru/e000.htm|title=Moose as a domestic animal|publisher=The Kostroma moose farm|url-status=live|archive-url=https://web.archive.org/web/20161210121333/http://www.moose-farm.ru/e000.htm|archive-date=December 10, 2016}}</ref>]]
In [[moose]], antlers may act as large hearing aids.  Equipped with large, highly adjustable external ears, moose have highly sensitive hearing.  Moose with antlers have more sensitive hearing than moose without, and a study of trophy antlers with an artificial ear confirmed that the large flattened (palmate) antler behaves like a parabolic reflector.<ref>{{cite journal |doi=10.1007/s10344-007-0165-4 |title=Palmated antlers of moose may serve as a parabolic reflector of sounds |journal=European Journal of Wildlife Research |volume=54 |issue=3 |pages=533–5 |year=2008 |last1=Bubenik |first1=George A. |last2=Bubenik |first2=Peter G. |s2cid=44737101 |url=https://engagedscholarship.csuohio.edu/cgi/viewcontent.cgi?article=1221&context=scimath_facpub}}
*{{cite news |author=James Randerson |date=March 20, 2008 |title=Moose's sharp hearing is attributed to antlers |newspaper=The Guardian |url=https://www.theguardian.com/science/2008/mar/21/medicalresearch.animalbehaviour}}</ref>

== Diversification ==
The diversification of antlers, body size and tusks has been strongly influenced by changes in habitat and behavior (fighting and mating).<ref name="Gilbert">{{cite journal |doi=10.1016/j.ympev.2006.02.017 |pmid=16584894 |title=Mitochondrial and nuclear phylogenies of Cervidae (Mammalia, Ruminantia): Systematics, morphology, and biogeography |journal=Molecular Phylogenetics and Evolution |volume=40 |issue=1 |pages=101–17 |year=2006 |last1=Gilbert |first1=Clément |last2=Ropiquet |first2=Anne |last3=Hassanin |first3=Alexandre |bibcode=2006MolPE..40..101G }}</ref>

=== Capreolinae ===
<gallery mode="packed" heights="128">
File:Caribou.jpg|[[Porcupine caribou]]
File:MuleDeer ModocCounty.jpg|A [[mule deer]] with relatively large antlers
File:White-tailed deer.jpg|[[White-tailed deer]]
File:Bristol.zoo.southern.pudu.arp.jpg|[[Pudú]]
File:Moose superior.jpg|[[Moose]]
</gallery>

=== Cervinae ===
<gallery mode="packed" heights="120">
Geweih eines Riesenhirsches.jpg|[[Irish elk]], [[Extinction|extinct]] species
Red_deer_stag.jpg|Young red deer, with velvet
Dama dama8.JPG|Fallow deer
Wapiti.Nebraska.JPG|American elk, or wapiti
Sambar deer.JPG|Sambar deer with thick, forked beams for antlers.
Flickr - Rainbirder - Cheetal Stag.jpg|[[Chital]]
</gallery>

== Homology and evolution of tines ==
[[File:Antler phylogenetics - Samejima et al 2020.png|thumb|right|300px|Antler phylogenetics]]
Antlers originated once in the cervid lineage.<ref name=":0">{{Cite journal|last=Heckeberg|first=Nicola S.|date=February 18, 2020|title=The systematics of the Cervidae: a total evidence approach|journal=PeerJ|language=en|volume=8|pages=e8114|doi=10.7717/peerj.8114|issn=2167-8359|pmc=7034380|pmid=32110477 |doi-access=free }}</ref> The earliest fossil remains of antlers that have been found are dated to the early Miocene, about 17 million years ago. These early antlers were small and had just two forks.<ref name=":0" /> As antlers evolved, they lengthened and gained many branches, or tines, becoming more complex.<ref name=":0" /> The homology of tines has been discussed since the 1900s and has provided great insight into the evolutionary history of the Cervidae family.<ref>Garrod, A. Notes on the visceral anatomy and osteology of the ruminants, with a suggestion regarding a method of expressing the relations of species by means of formulae. Proceedings of the Zoological Society of London, 2–18 (1877).</ref><ref>Brooke, V. On the classification of the Cervidæ, with a synopsis of the existing Species. Journal of Zoology 46, 883–928 (1878).</ref><ref>Pocock, R. The Homologies between the Branches of the Antlers of the Cervidae based on the Theory of Dichotomous Growth. Journal of Zoology 103, 377–406 (1933).</ref>

Recently, a new method to describe the branching structure of antlers was developed.<ref>Samejima, Y., Matsuoka, H. A new viewpoint on antlers reveals the evolutionary history of deer (Cervidae, Mammalia). Sci Rep 10, 8910 (2020). https://doi.org/10.1038/s41598-020-64555-7</ref> It is by using antler grooves, which are formed on the surface of antlers by growth, projecting the branching structure on the burr circumference, and making diagrams. Comparing the positional order among species on the diagram, the tine on the same position is homologous. The study revealed that three-pointed structures of Capreolinae and Cervini are homoplasious, and their subclades gained synapomorphous tines.

== Exploitation by other species ==

=== Ecological role ===
Discarded antlers represent a source of calcium, phosphorus and other minerals and are often gnawed upon by small animals, including squirrels, porcupines, rabbits and mice. This is more common among animals inhabiting regions where the soil is deficient in these minerals. Antlers shed in oak forest inhabited by squirrels are rapidly chewed to pieces by them.<ref name="FeldhamerMcShea2012"/><ref>{{cite book|author=Dennis Walrod|title=Antlers: A Guide to Collecting, Scoring, Mounting, and Carving|url=https://books.google.com/books?id=Qu_11ACcw4YC&pg=PA47|year=2010|publisher=Stackpole Books|isbn=978-0-8117-0596-7|page=46}}</ref>

=== Trophy hunting ===
Antlered heads are prized as [[trophy hunting|trophies]] with larger sets being more highly prized.  The first organization to keep records of sizes was [[Rowland Ward]] Ltd., a London [[taxidermy]] firm, in the early 20th century.  For a time only total length or spread was recorded.  In the middle of the century, the [[Boone and Crockett Club]] and the [[Safari Club International]] developed complex scoring systems based on various dimensions and the number of tines or points, and they keep extensive records of high-scoring antlers.<ref>{{cite book |last1=Bauer |first1=Erwin A. |last2=Bauer |first2=Peggy |year=2000 |title=Antlers: Nature's Majestic Crown |publisher=Voyageur Press |pages=20–1 |isbn=978-1-61060-343-0}}</ref> Deer bred for hunting on farms are selected based on the size of the antlers.<ref>{{cite web|last1=Laskow|first1=Sarah|title=Antler Farm|url=https://medium.com/re-form/antler-farm-dbd3ba1ec3f2|website=[[Medium (service)]]|date=August 27, 2014|access-date=August 28, 2014|url-status=live|archive-url=https://web.archive.org/web/20140903125220/https://medium.com/re-form/antler-farm-dbd3ba1ec3f2|archive-date=September 3, 2014}}</ref>

Hunters have developed terms for antler parts: beam, palm, brow, bez or bay, trez or tray, royal, and surroyal. These are the main shaft, flattened center, first [[Tine (structural)|tine]], second tine, third tine, fourth tine, and fifth or higher tines, respectively.<ref>{{cite web | url=http://www.wildlifeonline.me.uk/questions_answers_deer.html#antlers | title=Wildlifeonline – Questions & Answers – Deer | access-date=March 1, 2012 | url-status=live | archive-url=https://web.archive.org/web/20120115023803/http://www.wildlifeonline.me.uk/questions_answers_deer.html#antlers | archive-date=January 15, 2012 }}</ref> The second branch is also called an advancer.

In [[Yorkshire]] in the United Kingdom roe deer hunting is especially popular due to the large antlers produced there. This is due to the high levels of chalk in Yorkshire. The chalk is high in calcium which is ingested by the deer and helps growth in the antlers.<ref name="Fieldsports Britain">{{cite web|last=Fieldsports Britain|title=Fieldsports Britain: Grouse on the Glorious Twelfth, roebucks and|date=August 28, 2009 |url=https://www.youtube.com/watch?v=xdmcYQyWWKk&feature |archive-url=https://ghostarchive.org/varchive/youtube/20211211/xdmcYQyWWKk| archive-date=2021-12-11 |url-status=live|publisher=fieldsportschannel.tv|access-date=October 30, 2012}}{{cbignore}}</ref>

===Shed antler hunting===
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Gathering shed antlers or "sheds" attracts dedicated practitioners who refer to it colloquially as ''shed hunting'', or ''bone picking''. In the United States, the middle of December to the middle of February is considered shed hunting season, when deer, [[elk]], and moose begin to shed. The North American Shed Hunting Club, founded in 1991, is an organization for those who take part in this activity.<ref name="FeldhamerMcShea2012">{{cite book|author1=George A. Feldhamer|author2=William J. McShea|title=Deer: The Animal Answer Guide|url=https://books.google.com/books?id=ePTueMAGXWEC&pg=PA32|date=January 26, 2012|publisher=JHU Press|isbn=978-1-4214-0387-8|pages=32–}}</ref>

In the United States in 2017 sheds fetch around US$10 per pound, with larger specimens in good condition attracting higher prices. The most desirable antlers have been found soon after being shed. The value is reduced if they have been damaged by weathering or being gnawed by small animals. A matched pair from the same animal is a very desirable find but often antlers are shed separately and may be separated by several miles. Some enthusiasts for shed hunting use trained dogs to assist them.<ref>{{cite book|author=Dennis Walrod|title=Antlers: A Guide to Collecting, Scoring, Mounting, and Carving|url=https://books.google.com/books?id=Qu_11ACcw4YC&pg=PA47|year=2010|publisher=Stackpole Books|isbn=978-0-8117-0596-7|pages=44–52}}</ref> Most hunters will follow "game trails" (trails where deer frequently run) to find these sheds or they will build a shed trap to collect the loose antlers in the late winter/early spring.

In most US states, the possession of or trade in parts of game animals is subject to some degree of regulation, but the trade in antlers is widely permitted.<ref name="Walrod2010">{{cite book|author=Dennis Walrod|title=Antlers: A Guide to Collecting, Scoring, Mounting, and Carving|url=https://books.google.com/books?id=Qu_11ACcw4YC&pg=PA47|year=2010|publisher=Stackpole Books|isbn=978-0-8117-0596-7|pages=46–47}}</ref> In the national parks of Canada, the removal of shed antlers is an offense punishable by a maximum fine of C$25,000, as the Canadian government considers antlers to belong to the people of Canada and part of the ecosystems in which they are discarded.<ref>{{cite news |title=Parks Canada reminds visitors you can look, but don't touch |author=Susan Quinlan |url=http://content.yudu.com/Library/A1uowk/PrairiePostWestNovem/resources/3.htm |newspaper=Prairie Post West |date=November 18, 2011 |access-date=December 5, 2011 |page=3 |url-status=live |archive-url=https://web.archive.org/web/20150206135357/http://content.yudu.com/Library/A1uowk/PrairiePostWestNovem/resources/3.htm |archive-date=February 6, 2015 }}</ref>

<gallery widths="200px" heights="160px">
File:Moose Antlers in Denali National Park.JPG|A shed moose antler in [[Denali National Park and Preserve]], [[Alaska]] (2010)
File:Antlers found shortly after being shed by a deer in Eastern Oklahoma.jpg|Antlers found shortly after being shed by a whitetail deer in eastern [[Oklahoma]]
</gallery>

=== Carving for decorative and tool uses ===
[[File:Wallace CollectionDSCF7493.JPG|thumb|upright|A German [[powder flask]] made from a red deer antler, {{c.|1570}}. [[Wallace Collection]], London (2010)]]

Antler has been used through history as a material to make tools, weapons, ornaments, and toys.<ref>{{cite book |last1=Bauer |first1=Erwin A. |last2=Bauer |first2=Peggy |year=2000 |title=Antlers: Nature's Majestic Crown |publisher=Voyageur Press |page=7 |isbn=978-1-61060-343-0}}</ref> It was an especially important material in the European Late [[Paleolithic]], used by the [[Magdalenian]] culture to make carvings and engraved designs on objects such as the so-called [[Bâton de commandement]]s and the ''[[Bison Licking Insect Bite]]''.  In the Viking Age and medieval period, it formed an important raw material in the craft of comb-making. In later periods, antler—used as a cheap substitute for [[ivory]]—was a material especially associated with equipment for [[hunting]], such as saddles and horse harness, guns and daggers, [[powder flask]]s, as well as buttons and the like. The decorative display of wall-mounted pairs of antlers has been popular since medieval times at least.{{citation needed|date=April 2015}}

The [[Netsilik]], an [[Inuit]] group, made bows and arrows using antler, reinforced with strands of animal tendons braided to form a [[cable-backed bow]].<ref>{{cite book |last1=Balikci |first1=Asen |title=The Netsilik Inuit |date=1989 |publisher=Waveland Press |pages=38–39}}</ref> Several [[Indigenous peoples of the Americas|Indigenous American]] tribes also used antler to make bows, gluing tendons to the bow instead of tying them as cables. An antler bow, made in the early 19th century, is on display at [[Brooklyn Museum]]. Its manufacture is attributed to the [[Yankton Sioux]].<ref>{{cite web |url=https://www.brooklynmuseum.org/opencollection/objects/63442 |title=Bow, Bow Case, Arrows and Quiver|website=Brooklyn Museum}}</ref>

Through history large deer antler from a suitable species (e.g. [[red deer]]) were often cut down to its shaft and its lowest [[Tine (structural)|tine]] and used as a one-pointed [[pickax]].<ref>{{cite web |url=http://www.ingenious.org.uk/See/Tradeandindustry/Handandmachinetools/?target=SeeMedium&ObjectID=%7BB316DA4B-0B90-D31E-C28F-94EC504B8D04%7D&viewby=images |title=Deer-antler pick, used in flint mining from Grimes Graves |access-date=July 6, 2012 |url-status=live |archive-url=https://web.archive.org/web/20120308102837/http://www.ingenious.org.uk/See/Tradeandindustry/Handandmachinetools/?target=SeeMedium&ObjectID=%7BB316DA4B-0B90-D31E-C28F-94EC504B8D04%7D&viewby=images |archive-date=March 8, 2012 }}{{full citation needed|date=April 2015}}</ref><ref>{{cite web |title=970747.JPG |url=http://www.dkimages.com/discover/previews/847/970747.JPG |url-status=dead |archive-url=https://web.archive.org/web/20110725165301/http://www.dkimages.com/discover/previews/847/970747.JPG |archive-date=July 25, 2011 |publisher=DK Images |access-date=28 December 2022 }}</ref>

=== Ceremonial roles ===
Antler headdresses were worn by [[shaman]]s and other spiritual figures in various cultures, and for dances; 21 antler "frontlets" apparently for wearing on the head, and over 10,000 years old, have been excavated at the English [[Mesolithic]] site of [[Starr Carr]].  Antlers are still worn in traditional dances such as [[Yaqui people|Yaqui]] [[Yaqui music|deer dances]] and carried in the [[Abbots Bromley Horn Dance]].{{citation needed|date=April 2015}}

=== Dietary usage ===
In the [[velvet antler]] stage, antlers of elk and deer have been used in Asia as a [[dietary supplement]] or [[Chinese traditional medicine|alternative medicinal substance]] for more than 2,000 years.<ref>{{cite web|url=http://www.vitaminsinamerica.com/news/velvet.htm|title=Velvet Antler – Research Summary|website=www.vitaminsinamerica.com|access-date=May 1, 2018|url-status=live|archive-url=https://web.archive.org/web/20171018172436/http://www.vitaminsinamerica.com/news/velvet.htm|archive-date=October 18, 2017}}</ref> Recently, deer antler [[extract]] has become popular among Western athletes and [[body builders]] because the extract, with its trace amounts of [[IGF-1]], is believed to help build and repair [[muscle tissue]]; however, one [[double-blind]] study did not find evidence of intended effects.<ref>DiSalvo (September 18, 2015). How to Squeeze Snake Oil from Deer Antlers and Make Millions. [1] forbes.com</ref><ref>{{cite journal |pmid=14669926 |url=http://journals.humankinetics.com/ijsnem-back-issues/IJSNEMVolume13Issue3September/TheEffectsofDeerAntlerVelvetExtractorPowderSupplementationonAerobicPowerErythropoiesisandMuscularStrengthandEnduranceCharacteristics |year=2003 |last1=Sleivert |first1=G |title=The effects of deer antler velvet extract or powder supplementation on aerobic power, erythropoiesis, and muscular strength and endurance characteristics |journal=International Journal of Sport Nutrition and Exercise Metabolism |volume=13 |issue=3 |pages=251–65 |last2=Burke |first2=V |last3=Palmer |first3=C |last4=Walmsley |first4=A |last5=Gerrard |first5=D |last6=Haines |first6=S |last7=Littlejohn |first7=R |doi=10.1123/ijsnem.13.3.251 }}</ref>

Elk, deer, and moose antlers have also become popular forms of dog chews that owners purchase for their pet canines.

=== Shed hunting with dogs ===
Dogs are sometimes used to find shed antlers. The North American Shed Hunting Dog Association (NASHDA)<ref>[https://www.sheddogtrainer.com/ North American Shed Hunting Dog Association]</ref> has resources for people who want to train their dogs to find shed antlers and hold shed dog hunting events.

==References==
{{reflist|30em}}
{{1728|title=antler|url=https://search.library.wisc.edu/digital/A4C5AV6Q7LZ5DY8E/pages/A3LMVB46HUL6DC9A|volume=1|page=113}}

==External links==
{{Commons category|Antlers}}

{{Authority control}}

[[Category:Bone products]]
[[Category:Mammal anatomy]]