Editing Deer (section)

==Biology==

[[File:Roe deer eating leaves in Tuntorp 2.jpg|thumb|A [[Roe deer]] browsing tree leaves in [[Brastad]], Sweden]]

===Diet===

Deer are [[herbivore|browsers]], and feed primarily on foliage of [[Poaceae|grasses]], [[sedge]]s, [[forb]]s, [[shrub]]s and [[tree]]s, secondarily on [[lichen]]s in northern latitudes during winter.<ref>Uresk, Daniel W., and Donald R. Dietz. "Fecal vs. Rumen Contents to Determine White-tailed Deer Diets." Intermountain Journal of Sciences 24, no. 3-4 (2018): 118–122.</ref> They have small, unspecialized stomachs by [[ruminant]] standards, and high nutrition requirements. Rather than eating and digesting vast quantities of low-grade fibrous food as, for example, [[domestic sheep|sheep]] and [[cattle]] do, deer select easily digestible shoots, young leaves, fresh grasses, soft twigs, fruit, [[fungus|fungi]], and [[lichen]]s. The low-fibered food, after minimal fermentation and shredding, passes rapidly through the alimentary canal. The deer require a large amount of minerals such as [[calcium]] and phosphate in order to support antler growth, and this further necessitates a nutrient-rich diet. There are some reports of deer engaging in carnivorous activity, such as eating dead [[alewife (fish)|alewives]] along lakeshores<ref name=Case1987>{{cite journal |last1= Case |first1= D.J. |last2= McCullough |first2= D.R.  |date= February 1987 |title= White-tailed deer forage on alewives |journal= Journal of Mammalogy |volume= 68 |issue= 1 |pages= 195–198 |doi= 10.2307/1381075|jstor= 1381075 }}</ref> or depredating the nests of [[northern bobwhite]]s.<ref>{{cite journal | last1 = Ellis-Felege | first1 = S. N. | last2 = Burnam | first2 = J. S. | last3 = Palmer | first3 = W. E. | last4 = Sisson | first4 = D. C. | last5 = Wellendorf | first5 = S. D. | last6 = Thornton | first6 = R. P. | last7 = Stribling | first7 = H. L. | last8 = Carroll | first8 = J. P. | year = 2008 | title = Cameras identify White-tailed deer depredating Northern bobwhite nests| journal = Southeastern Naturalist | volume = 7 | issue = 3| pages = 562–564 | doi=10.1656/1528-7092-7.3.562| s2cid = 84790827 }}</ref>

===Reproduction===

{{main|Rut (mammalian reproduction)#Cervidae}}
[[File:Wapiti (01) 2006-09-19.JPG|left|thumb|Female [[elk]] nursing young]]
Nearly all cervids are so-called [[wikt:uniparental|uniparental]] species: the young, known in most species as fawns, are only cared for by the mother, most often called a doe. A doe generally has one or two fawns at a time (triplets, while not unknown, are uncommon). Mating season typically begins in later August and lasts until December. Some species mate until early March. The [[gestation period]] is anywhere up to ten months for the European roe deer. Most fawns are born with their fur covered with white spots, though in many species they lose these spots by the end of their first winter. In the first twenty minutes of a fawn's life, the fawn begins to take its first steps. Its mother licks it clean until it is almost free of scent, so [[predator]]s will not find it. Its mother leaves often to graze, and the fawn does not like to be left behind. Sometimes its mother must gently push it down with her foot.<ref name="Ref_a">[http://www.sheppardsoftware.com/content/animals/animals/mammals/deer.htm Deer – info and games] Sheppard Software.</ref>{{better source needed|date=December 2020}} The fawn stays hidden in the grass for one week until it is strong enough to walk with its mother. The fawn and its mother stay together for about one year. A male usually leaves and never sees his mother again, but females sometimes come back with their own fawns and form small herds.

===Disease===

In some areas of the UK, deer (especially [[fallow deer]] due to their [[gregarious behaviour]]) have been implicated as a possible reservoir for transmission of [[bovine tuberculosis]],<ref name="Delahay et al., 2007">{{cite journal|last1=Delahay |first1=R. J. |last2=Smith |first2=G. C. |last3=Barlow |first3=A. M. |last4=Walker |first4=N. |last5=Harris |first5=A. |last6=Clifton-Hadley |first6=R. S. |last7=Cheeseman |first7=C. L. |year=2007 |title=Bovine tuberculosis infection in wild mammals in the South-West region of England: A survey of prevalence and a semi-quantitative assessment of the relative risks to cattle |journal=The Veterinary Journal |volume=173 |pages= 287–301 |pmid=16434219 |doi=10.1016/j.tvjl.2005.11.011 |issue=2}}</ref><ref name="Ward et al., 2009">{{cite journal |last1=Ward |first1=A. I. |last2=Smith |first2=G. C. |last3=Etherington |first3=T. R. |last4=Delahay |first4=R. J. |year=2009 |title=Estimating the risk of cattle exposure to tuberculosis posed by wild deer relative to badgers in England and Wales|pmid=19901384 |journal=Journal of Wildlife Diseases |volume= 45 |pages=1104–1120 |issue=4 |doi=10.7589/0090-3558-45.4.1104|s2cid=7102058 |doi-access=free }}</ref> a disease which in the UK in 2005 cost £90&nbsp;million in attempts to eradicate.<ref name="The Vet Record, 2008">{{cite journal|author=Anonymous |year=2008|title=Bovine TB: EFRACom calls for a multifaceted approach using all available methods |journal=The Veterinary Record |volume=162 |pages=258–259 |pmid=18350673 |doi=10.1136/vr.162.9.258 |issue=9|s2cid=2429198}}</ref> In New Zealand, deer are thought to be important as vectors picking up ''M. bovis'' in areas where brushtail possums ''[[Trichosurus vulpecula]]'' are infected, and transferring it to previously uninfected possums when their carcasses are scavenged elsewhere.<ref name="Delehay et al, 2002">{{cite journal |last1=Delahay |first1=R. J. |last2=De Leeuw |first2=A. N. S. |last3=Barlow |first3=A. M. |last4=Clifton-Hadley |first4=R. S. |last5=Cheeseman |first5=C. L. |year=2002 |title=The status of Mycobacterium bovis infection in UK wild mammals: A review |journal=The Veterinary Journal |volume=164 |pages=90–105 |pmid=12359464 |doi=10.1053/tvjl.2001.0667 |issue=2}}</ref> The white-tailed deer ''[[Odocoileus virginianus]]'' has been confirmed as the sole maintenance host in the Michigan outbreak of bovine tuberculosis which remains a significant barrier to the US nationwide eradication of the disease in livestock.<ref name="O'Brien et al., 2011">{{cite journal |last1=O'Brien |first1=D. J. |last2=Schmitt |first2=S. M. |last3=Fitzgerald |first3=S. D. |last4=Berry |first4=D. E. |year=2011 |title=Management of bovine tuberculosis in Michigan wildlife: Current status and near term prospects |pmid=21414734 |journal=Veterinary Microbiology |volume=151 |pages=179–187 |doi=10.1016/j.vetmic.2011.02.042 |issue=1–2|url=https://zenodo.org/record/1000720 }}</ref> Moose and deer can carry [[rabies]].<ref name="mtt">{{cite news|publisher=Moncton Times&Transcript|title=Don't fraternize with wild animals: biologist|author=Alan Cochrane|date=January 2019}}</ref>

Docile moose may suffer from [[brain worm]], a [[parasitic worm|helminth]] which drills holes through the brain in its search for a suitable place to lay its eggs. A government biologist states that "They move around looking for the right spot and never really find it." Deer appear to be immune to this parasite; it passes through the digestive system and is excreted in the feces. The parasite is not screened by the moose intestine, and passes into the brain where damage is done that is externally apparent, both in behaviour and in gait.<ref name=mtt/>

Deer, elk and moose in North America may suffer from [[chronic wasting disease]], which was identified at a [[Colorado]] laboratory in the 1960s and is believed to be a prion disease. Out of an abundance of caution hunters are advised to avoid contact with [[specified risk material]] (SRM) such as the brain, spinal column or lymph nodes. Deboning the meat when butchering and sanitizing the knives and other tools used to butcher are amongst other government recommendations.<ref>{{cite web|url=http://www.dnr.state.md.us/wildlife/Hunt_Trap/deer/disease/cwdinformation.asp|archive-url=https://web.archive.org/web/20130514234545/http://www.dnr.state.md.us/wildlife/Hunt_Trap/deer/disease/cwdinformation.asp|url-status=dead|archive-date=2013-05-14|title=Wildlife and Heritage Service : Chronic Wasting Disease (CWD)|publisher=Maryland Department of Natural Resources}}</ref>