Editing Deer (section)

===Antlers===

{{main|Antler}}
[[File:White-tailed deer.jpg|thumb|left|[[White-tailed deer]]]]
All male deer have [[antler]]s, with the exception of the [[water deer]], in which males have long tusk-like canines that reach below the lower jaw.<ref name="BurtonChinese">{{cite book|last1=Burton|first1=M.|last2=Burton|first2=R.|title=International Wildlife Encyclopedia|date=2002|publisher=Marshall Cavendish|location=New York, US|isbn=978-0-7614-7270-4|pages=[https://archive.org/details/internationalwil04burt0/page/446 446–7]|edition=3rd|url=https://archive.org/details/internationalwil04burt0/page/446}}</ref> Females generally lack antlers, though female reindeer bear antlers smaller and less branched than those of the males.<ref name="Hall2005">{{cite book|last1=Hall|first1=B. K.|title=Bones and Cartilage: Developmental and Evolutionary Skeletal Biology|date=2005|publisher=Elsevier Academic Press|location=Amsterdam, Netherlands|isbn=978-0-08-045415-3|pages=103–15|url={{Google Books|id=y-RWPGDONlIC|page=103|plainurl=yes}}}}</ref> Occasionally females in other species may develop antlers, especially in telemetacarpal deer such as European roe deer, red deer, white-tailed deer and mule deer and less often in plesiometacarpal deer. A study of antlered female white-tailed deer noted that antlers tend to be small and malformed, and are shed frequently around the time of parturition.<ref>{{cite journal|last1=Wislocki|first1=G. B.|title=Antlers in female deer, with a report of three cases in ''Odocoileus''|journal=Journal of Mammalogy|date=1954|volume=35|issue=4|pages=486–95|jstor=1375571|doi=10.2307/1375571}}</ref>

[[File:Antler phylogenetics - Samejima et al 2020.png|thumb|Antler phylogenetics]]
The fallow deer and the various subspecies of the reindeer have the largest as well as the heaviest antlers, both in absolute terms as well as in proportion to body mass (an average of eight grams per kilogram of body mass);<ref name="Hall2005" /><ref>{{cite book|last1=Smith|first1=T.|title=The Real Rudolph: A Natural History of the Reindeer|date=2013|publisher=The History Press|location=New York, US|isbn=978-0-7524-9592-7|url={{Google Books|id=MDA9AwAAQBAJ|page=PT18|plainurl=yes}}}}</ref> the tufted deer, on the other hand, has the smallest antlers of all deer, while the pudú has the lightest antlers with respect to body mass (0.6&nbsp;g per kilogram of body mass).<ref name="Hall2005" /> The structure of antlers show considerable variation; while fallow deer and elk antlers are palmate (with a broad central portion), white-tailed deer antlers include a series of tines sprouting upward from a forward-curving main beam, and those of the pudú are mere spikes.<ref name="Geist" /> Antler development begins from the pedicel, a bony structure that appears on the top of the skull by the time the animal is a year old. The pedicel gives rise to a spiky antler the following year, that is replaced by a branched antler in the third year. This process of losing a set of antlers to develop a larger and more branched set continues for the rest of the life.<ref name="Hall2005" /> The antlers emerge as soft tissues (known as [[velvet antler]]s) and progressively harden into bony structures (known as hard antlers), following [[Mineralization (biology)|mineralisation]] and blockage of [[blood vessel]]s in the tissue, from the tip to the base.<ref>{{cite book|last1=Fletcher|first1=T. J.|editor1-last=Alexander|editor1-first=T. L.|editor2-last=Buxton|editor2-first=D.|title=Management and Diseases of Deer: A Handbook for the Veterinary Surgeon|date=1986|publisher=Veterinary Deer Society|location=London, UK|isbn=978-0-9510826-0-7|pages=17–8|edition=2nd|chapter=Reproduction: seasonality}}</ref>

[[File:Sambar deers Fighting Silvassa.jpg|right|thumb|Two [[Sambar deer]] fighting, [[Silvassa]], India]]
Antlers might be one of the most exaggerated male [[secondary sexual characteristic]]s,<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 are intended primarily for reproductive success through [[sexual selection]] and for combat. The tines (forks) on the antlers create grooves that allow another male's antlers to lock into place. This allows the males to wrestle without risking injury to the face.<ref>{{cite journal | last1=Emlen | first1=D. J. | year=2008 | title=The evolution of animal weapons | journal=Annual Review of Ecology, Evolution, and Systematics | volume=39 | pages=387–413 | doi=10.1146/annurev.ecolsys.39.110707.173502}}</ref> Antlers are correlated to an individual's position in the social hierarchy and its behaviour. For instance, the heavier the antlers, the higher the individual's status in the social hierarchy, and the greater the delay in shedding the antlers;<ref name=Hall2005/> males with larger antlers tend to be more aggressive and dominant over others.<ref>{{cite journal|last1=Bowyer|first1=R. T.|title=Antler characteristics as related to social status of male southern mule deer|journal=The Southwestern Naturalist|date=1986|volume=31|issue=3|pages=289–98|jstor=3671833|doi=10.2307/3671833|bibcode=1986SWNat..31..289B }}</ref> Antlers can be an [[honest signal]] of genetic quality; males with larger antlers relative to body size tend to have increased resistance to [[pathogen]]s<ref>{{cite journal | last1=Ditchkoff | first1=S. S. | last2=Lochmiller | first2=R. L. | last3=Masters | first3=R. E. | last4=Hoofer | first4=S. R. | last5=Den Bussche | first5=R. A. Van | year=2001 | 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=616–625 | doi=10.1111/j.0014-3820.2001.tb00794.x | pmid=11327168| s2cid=10418779 | doi-access=free }}</ref> and higher reproductive capacity.<ref>{{cite journal | last1=Malo | first1=A. F. | last2=Roldan | first2=E. R. S. | last3=Garde | first3=J. | last4=Soler | first4=A. J. | last5=Gomendio | first5=M. | year=2005 | title=Antlers honestly advertise sperm production and quality | journal=Proceedings of the Royal Society B: Biological Sciences | volume=272 | issue=1559 | pages=149–157 | doi=10.1098/rspb.2004.2933 | pmid=15695205 | pmc=1634960}}</ref>

In elk in [[Yellowstone National Park]], antlers also provide protection against predation by [[wolf|wolves]].<ref name=wolves>{{cite journal |title=Predation shapes the evolutionary traits of cervid weapons |journal=Nature Ecology & Evolution |date=2018-09-03 |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>

Homology of tines, that is, the branching structure of antlers among species, have been discussed before the 1900s.<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 and determining homology of tines 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>