Animal Diversity Web

Di­ver­sity

The fam­ily Cervi­dae, com­monly re­ferred to as "the deer fam­ily", con­sists of 23 gen­era con­tain­ing 47 species, and in­cludes three sub­fam­i­lies: Capri­oli­nae (brocket deer, cari­bou, deer, moose, and rel­a­tives), Cerv­inae elk, munt­jacs, and tufted deer), and Hy­dropoti­nae, which con­tains only one ex­tant species, Chi­nese water deer. How­ever, clas­si­fi­ca­tion of cervids has been con­tro­ver­sial and a sin­gle well-sup­ported phy­lo­ge­netic and tax­o­nomic his­tory has yet to be es­tab­lished. Cervids range in mass from 20 lbs to 1800 lbs, and all but one species, Chi­nese water deer, have antlers. With the ex­cep­tion of cari­bou, only males have antlers and some species with smaller antlers have en­larged upper ca­nines. In ad­di­tion to sex­u­ally di­mor­phic or­na­men­ta­tion, most deer species are size-di­mor­phic as well with males com­monly being 25% larger than their fe­male coun­ter­parts. Cervids have a large num­ber of mor­pho­log­i­cal synapo­mor­phies (e.g., char­ac­ter­is­tics that are shared within a tax­o­nomic group), and range in color from dark to very light brown; how­ever, young are com­monly born with cryp­tic col­oration, such as white spots, that helps cam­ou­flage them from po­ten­tial preda­tors. Cervids can be found in a wide range of habi­tats, from ex­tremely cold to the trop­ics. They have been in­tro­duced nearly world wide, but are na­tive through­out most of the New World, Eu­rope, Asia and north­west­ern Africa, with Eura­sia ex­hibit­ing the great­est species di­ver­sity. Al­though most cervids live in herds, some species, such as South Amer­i­can marsh deer, are soli­tary. The ma­jor­ity of species have so­cial hi­er­ar­chies that have a pos­i­tive cor­re­la­tion with body size (e.g., large males are dom­i­nant to small males). (Feld­hamer, et al., 2007; Ful­bright and Or­tega-S., 2006; Herna ́ndez Ferna ́ndez and Vrba, 2005; Huff­man, 2010; Vaughan, et al., 2000)

Ge­o­graphic Range

Cervids are widely dis­trib­uted and are na­tive to all con­ti­nents ex­cept Aus­tralia, Antarc­tica, and most of Africa, which con­tains only a sin­gle sub-species of na­tive deer, Bar­bary red deer. Cervids have been in­tro­duced nearly world­wide and there are now 6 in­tro­duced species of deer in Aus­tralia and New Zealand that have been es­tab­lished since the mid 1800s. (Bauer, 1985; Feld­hamer, et al., 2007; Huff­man, 2010; Vaughan, et al., 2000)

• Biogeographic Regions
• nearctic
  • native
• palearctic
  • native
• oriental
  • native
• ethiopian
  • native
• neotropical
  • native
• australian
  • introduced
• oceanic islands
  • introduced

Habi­tat

Cervids live in a va­ri­ety of habi­tats, rang­ing from the frozen tun­dra of north­ern Canada and Green­land to the equa­to­r­ial rain forests of India, which has the largest num­ber of deer species in the world. They in­habit de­cid­u­ous forests, wet­lands, grass­lands, arid scrub­lands, rain forests, and are par­tic­u­larly well suited for bo­real and alpine ecosys­tems. Many species are par­tic­u­larly fond of for­est-grass­land eco­tones and are known to re­side a va­ri­ety of urban and sub­ur­ban set­tings. (Feld­hamer, et al., 2007; Ful­bright and Or­tega-S., 2006; Vaughan, et al., 2000)

• Habitat Regions
• temperate
• tropical
• polar
• terrestrial

• Terrestrial Biomes
• tundra
• taiga
• desert or dune
• savanna or grassland
• chaparral
• forest
• rainforest
• scrub forest
• mountains

• Wetlands
• marsh
• swamp
• bog

• Other Habitat Features
• urban
• suburban
• agricultural

Sys­tem­atic and Tax­o­nomic His­tory

As is the case with many fam­i­lies within the order Ar­tio­dactyla, a well-sup­ported sys­tem­atic and tax­o­nomic his­tory of Cervi­dae has yet to be es­tab­lished. Ac­cord­ing to Gilbert et al. (2006), which used mi­to­chon­dr­ial and nu­clear DNA to de­ter­mine the phy­lo­ge­netic re­la­tion­ship be­tween species, Cervi­dae can be bro­ken down into two sub­fam­i­lies, Cerv­inae and Capri­oli­nae. How­ever, Her­nan­dez-Fer­nan­dez and Vrba (2005) pro­vide sup­port for 3 sub­fam­i­lies, Hy­dropoti­nae, Cerv­inae, and Odocoileinae. Re­gard­less, most re­cent clas­si­fi­ca­tion at­tempts in­cor­po­rate dif­fer­ences in the gross mor­phol­ogy of the metacarpals. Those species that re­tain the prox­i­mal por­tion of the lat­eral metacarpals are grouped into Ple­siometacarpalia (Cerv­inae and Cerv­inae), and those that re­tain the dis­tal por­tion of the lat­eral metacarpals are grouped into Telemetacarpalia (Odocoileinae and Hy­dropoti­nae). Tra­di­tion­ally, Cervi­dae has con­sisted of 3 sub­fam­i­lies: Capre­oli­nae (brocket deer, cari­bou, deer, moose, and rel­a­tives), Cerv­inae (elk, munt­jacs, and tufted deer), and Hy­dropoti­nae (water deer). The fam­ily Moschi­dae, the musk deer, which are known for their large upper ca­nines, was once a sub­fam­ily of Cervi­dae but is now con­sid­ered a sep­a­rate fam­ily. (Clément, et al., 2006; Danilkin, 1996; Herna ́ndez Ferna ́ndez and Vrba, 2005; Hiller, 1996; Put­nam, 1989; White­head, 1972)

All ex­tinct and liv­ing deer are thought to have evolved dur­ing the Miocene and early Pliocene from a Eurasian an­ces­tor known as pro­todeer (Di­cro­ceri­dae). The first true cervids ap­peared about 20 mil­lion years ago dur­ing the early Miocene, which is around the same time cervids began mov­ing from Asia into Eu­rope and North Amer­ica. Early cervids began move­ment into North Amer­ica via the Be­ri­gian Land Bridge and be­came rel­a­tively com­mon in North Amer­ica dur­ing the early Pliocene. Some Pleis­tocene cervids had spec­tac­u­lar antlers. For ex­am­ple, the "Irish elk" Mega­lo­ceros, which was not an elk and was not re­stricted to Ire­land, had large palmate antlers with a span up to 3.7 m and a weight around 45 kg. In North Amer­ica, the giant stag moose had tri­palmate antlers that spanned al­most 5 feet in width. An­other ex­tinct deer with spec­tac­u­lar antlers was Eu­clado­ceros, a large an­i­mal whose antlers were made up of many of ir­reg­u­larly branched tines. Synapo­mor­phies of ex­tant cervids in­clude de­cid­u­ous antlers, no upper in­cisors, two lacrimal ori­fices on or out­side the or­bital rim, and an eth­moidal or an­tor­bital vacu­ity that ter­mi­nates the lacrimal short of nasal ar­tic­u­la­tion. (Bar­banti-Duarte, et al., 2008; Bubenik, 2007; Janis and Scott, 1987)

• Synapomorphies

  • two deciduous antlers
  • two lacrimal orifices on or outside the orbital rim
  • antorbital vacuity that terminates the lacrimal short of nasal articulation
  • lack of upper incisors

Phys­i­cal De­scrip­tion

There is a great deal of phys­i­cal di­ver­sity within the fam­ily Cervi­dae. Moose, the largest ex­tant mem­ber of the fam­ily, can reach up to 1800 lbs and the small­est, north­ern pudu, reach a max­i­mum size of roughly 20 lbs. Typ­i­cally mem­bers have com­pact tor­sos and very pow­er­ful elon­gated legs that are well suited for woody or rocky ter­rain. With the ex­cep­tion of Chi­nese water deer, all male cervids have de­cid­u­ous antlers and cari­bou are the only species in which both males and fe­males have antlers. Deer are pri­mar­ily browsers (for­ag­ing on broad leaf plant ma­te­r­ial), and their low- (brachy­dont) to medium-crowned (mesodont) se­len­odont cheek teeth are highly spe­cial­ized for brows­ing. Cervids lack upper in­cisors and in­stead have a hard palate. The an­te­rior por­tion of the palate is cov­ered with a hard­ened tis­sue against which the lower in­cisors and ca­nines oc­clude. They have a 0/3, 0-1/1, 3/3, 3/3 den­tal for­mula. Other no­table fea­tures of cervids in­clude the lack of a sagit­tal crest and the pres­ence of a pos­tor­bital bar. (Danilkin, 1996; Ful­bright and Or­tega-S., 2006)

Antlers grow from pedicels, boney sup­port­ing struc­tures that grow on the lat­eral re­gions of the frontal bones. In tem­per­ate-zone cervids, antlers begin grow­ing in the spring as skin-cov­ered pro­jec­tions from the pedicels. The der­mal cov­er­ing, or "vel­vet," is rich in blood ves­sels and nerves. When antlers reach full size, the vel­vet dies and is rubbed off as the an­i­mal thrashes its antlers against veg­e­ta­tion. Antlers are used dur­ing male-male com­pe­ti­tion for mates dur­ing breed­ing sea­son, and are shed soon af­ter­wards. Typ­i­cally, only males bear antlers how­ever, both gen­ders bear antlers in cari­bou. Antlers vary from sim­ple spikes, such as those in mun­jacs, to enor­mous, com­plexly branched struc­tures, such as those in moose. Antler struc­ture changes de­pend­ing on species and the age of the in­di­vid­ual bear­ing them. Males of the genus Munti­acuc have both antlers and long, fang-like upper ca­nines that are used in so­cial dis­plays. Al­though Chi­nese water deer are the only species with­out antlers, they have elon­gated upper ca­nines that are used to at­tract mates. Antlers typ­i­cally emerge at one year of age. (Danilkin, 1996; Ful­bright and Or­tega-S., 2006)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• male larger
• sexes shaped differently
• ornamentation

Re­pro­duc­tion

Al­though most cervids are polyg­y­nous, some species are monog­a­mous (e.g., Eu­ro­pean Roe deer). The breed­ing sea­son of most cervids is short, with fe­males com­ing into es­trus in syn­chrony. In some species, males es­tab­lish ter­ri­to­ries, which en­com­pass those of one or more fe­males. Males may then mate with those fe­males who have ter­ri­to­ries within his own. In some cervids, fe­males may form small groups known as harems, which are guarded and main­tained by males, and in other species males sim­ply travel be­tween herds look­ing for es­trus fe­males. Sex­ual seg­re­ga­tion is not un­com­mon in cervids; how­ever, in some species per­ma­nent mixed-sex groups re­sult in male-male com­pe­ti­tion for po­ten­tial mates. In sex­u­ally seg­re­gat­ing species, males join fe­males only to cop­u­late, leav­ing at the end of breed­ing sea­son. Males es­tab­lish dom­i­nance hi­er­ar­chies among them­selves, with the most dom­i­nant males achiev­ing the most cop­u­la­tions. Males may hold dom­i­nance over a harem or ter­ri­tory and are often chal­lenged by rival males. Male cervids sig­nif­i­cantly de­crease for­age in­take dur­ing breed­ing sea­son, which, in con­junc­tion with being con­tin­u­ally chal­lenged by ri­vals males, en­sures that dom­i­nance by any one in­di­vid­ual is short lived. Antler growth is de­pen­dent on in­di­vid­ual nu­tri­tion and ev­i­dence sug­gests that the size and sym­me­try of male antlers serves as an in­di­ca­tor of mate qual­ity for fe­males. (Feld­hamer, et al., 2007; Miquelle, 1990; Put­nam, 1989)

• Mating System
• monogamous
• polygynous

Cervids liv­ing in tem­per­ate zones typ­i­cally breed dur­ing late au­tumn or early win­ter. Sea­sonal breed­ers at lower lat­i­tudes, such as the chi­tal, breed from late spring into early sum­mer (e.g., April or May). Con­cep­tion usu­ally oc­curs dur­ing the first es­trus cycle of the breed­ing sea­son, and those that do not con­ceive will re-en­ter es­trus every 18 days until they be­come preg­nant. Species liv­ing in trop­i­cal cli­mates, such as grey brocket deer, often do not have a fixed breed­ing sea­son, and fe­males may come in to es­trus mul­ti­ple times through­out the year. Ges­ta­tion in cervids ranges from 180 days in Chi­nese water deer to 240 days for elk, with larger species tend­ing to have longer ges­ta­tional pe­ri­ods. Roe deer are the only cervid known to have de­layed im­plan­ta­tion. Cervids typ­i­cally have from 1 to 3 off­spring, and often, not all fe­tuses are car­ried to term, as the num­ber of off­spring born each year is de­pen­dent on pop­u­la­tion den­sity and re­source abun­dance. Age at wean­ing varies among species, with smaller species nurs­ing for only 2 to 3 months and larger species nurs­ing for much longer. For ex­am­ple Bornean yel­low munt­jacs are weaned by about 2 months of age and North Amer­i­can moose are weaned by about 5 months, how­ever, er­ratic nurs­ing may con­tinue for up to 7 months after birth. (Feld­hamer, et al., 2007; Put­nam, 1989)

Body weight is more im­por­tance in de­ter­min­ing sex­ual ma­tu­rity in cervids than ac­tual age; there­fore, an in­di­vid­ual's re­pro­duc­tive ac­tiv­ity is de­pen­dent on en­vi­ron­men­tal con­di­tions and re­source qual­ity and abun­dance. Due to the en­er­getic costs of lac­ta­tion, this is es­pe­cially true for fe­males. In males, testes begin pro­duc­ing hor­mones at the end of the first year, and con­se­quently, antler growth oc­curs dur­ing the end of the first year or the be­gin­ning of the sec­ond. How­ever, be­cause male-male com­pe­ti­tion plays a dom­i­nant role in cervid mat­ing be­hav­ior, most males do not mate until they can out­com­pete ri­vals for ac­cess to fe­males. (Feld­hamer, et al., 2007; Put­nam, 1989)

Al­though some cervids are soli­tary, most are gre­gar­i­ous and live in herds that vary in size from a few in­di­vid­u­als to more than 100,000 (e.g., cari­bou. Av­er­age group size de­pends on the de­mo­graphic com­po­si­tion (i.e., sex and age) of the im­me­di­ate pop­u­la­tion, the de­gree of in­ter- and in­traspe­cific com­pe­ti­tion, and re­source qual­ity and abun­dance. Habi­tat seg­re­ga­tion in cervids tends to peak dur­ing calv­ing and sig­nif­i­cantly de­creases soon af­ter­ward. Most species are polyg­y­nous, and males use their antlers in com­bat to ob­tain and de­fend fe­males. Sex­ual-size di­mor­phism is com­mon in cervids. Males are larger than fe­males in most species, and sex­ual di­mor­phism is more pro­nounced in the most highly polyg­y­nous species. Cervids have a num­ber of glands on their feet, legs, and faces that are used dur­ing in­traspe­cific com­mu­ni­ca­tion. Males of many cervid species sig­nif­i­cantly de­crease for­age in­take dur­ing mat­ing sea­son, and ev­i­dence sug­gests that feed­ing ces­sa­tion in males is linked to var­i­ous phys­i­o­log­i­cal processes as­so­ci­ated with chem­i­cal com­mu­ni­ca­tion dur­ing the breed­ing sea­son. (Bowyer, et al., 2010; Bubenik, 2007; Feld­hamer, et al., 2007; Miquelle, 1990; Vaughan, et al., 2000)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• viviparous

As with many ar­tio­dactyls, cervids can be clas­si­fied as ei­ther hiders or fol­low­ers. Al­tri­cially born cervids are highly vul­ner­a­ble to pre­da­tion for the first few weeks of life. As a re­sult, moth­ers hide their young in the sur­round­ing veg­e­ta­tion as they for­age nearby. Hider moth­ers pe­ri­od­i­cally re­turn to their young through­out the day to nurse and clean their calves. Fe­males that give birth to mul­ti­ple off­spring hide each in­di­vid­ual in sep­a­rate lo­ca­tions, pre­sum­ably to de­crease the chance of los­ing mul­ti­ple young to a preda­tor. Once young be­come strong enough to es­cape po­ten­tial preda­tors they join their mother dur­ing for­ag­ing bouts. Some species are pre­co­cially born and are able to run only a few hours after birth (e.g., Rangifer taran­dus). These species are often re­ferred to as fol­low­ers. (Feld­hamer, et al., 2007; Put­nam, 1989)

Lac­ta­tion is one of the most en­er­get­i­cally ex­pen­sive ac­tiv­i­ties pos­si­ble for fe­male mam­mals and lac­tat­ing cervids are often not able to con­sume enough food to main­tain their body weight, es­pe­cially dur­ing the first weeks of lac­ta­tion. Typ­i­cally, young are weaned ear­lier in smaller species; how­ever, spo­radic nurs­ing may occur for up to 7 months after birth. Young cervids may stay with their mother until she is about to give birth to the sub­se­quent sea­son’s off­spring. In many species, fe­males stay within their mother’s range after mat­u­ra­tion, while males are forced to dis­perse. In most species, males do not pro­vide any parental care to their off­spring. (Feld­hamer, et al., 2007; Put­nam, 1989)

• Parental Investment
• female parental care
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • female
• post-independence association with parents

Lifes­pan/Longevity

The lifes­pan of most cervid ranges from 11 to 12 years, how­ever, many are killed be­fore their fifth birth­day due to var­i­ous causes in­clud­ing hunt­ing, pre­da­tion, or motor ve­hi­cle col­li­sions. In most species, males have shorter lifes­pans than fe­males and this is likely a re­sult of in­tra­sex­ual com­pe­ti­tion for mates and the soli­tary na­ture of most sex­u­ally di­mor­phic males, re­sult­ing in in­creased risk of pre­da­tion. How­ever, re­cent stud­ies show that sex-bi­ased mor­tal­ity rates are tightly linked to local en­vi­ron­men­tal con­di­tions. Cap­tive deer tend to out­live their wild coun­ter­parts as they are sub­jected to lit­tle or no pre­da­tion and have ac­cess to an abun­dant sup­ply of food. The lifes­pan of cervids de­creases as the num­ber of deer ex­ceeds the local en­vi­ron­ments car­ry­ing ca­pac­ity. In this case, young and old cervids tend to suf­fer from star­va­tion, as stronger, mid­dle-aged deer out­com­pete them for for­age. (Danilkin, 1996; Toigo C, et al., 2003; White­head, 1972)

Be­hav­ior

Al­though ac­tive through­out most of the day, cervids are typ­i­cally clas­si­fied as cre­pus­cu­lar. Species liv­ing in sea­sonal cli­mates spend most of their time dur­ing the win­ter and early spring rest­ing, as for­age dur­ing this time is lim­ited and of poor qual­ity. Dur­ing late spring, when fresh for­age is avail­able, deer spend less time rest­ing and sig­nif­i­cantly in­crease their ac­tiv­ity rates. Ac­tiv­ity pat­terns are based on sea­sonal meta­bolic rates and en­ergy costs, which change from sea­son to sea­son. Dur­ing sum­mer, en­ergy re­quire­ments are high and thus they spend more time for­ag­ing. Cervids tend to lose weight dur­ing win­ter due to a re­duc­tion in ap­petite and de­creased for­age qual­ity and avail­abil­ity. How­ever, many species found in habi­tats with min­i­mal cli­matic vari­abil­ity ex­hibit a re­duc­tion in food in­take and de­creased meta­bolic rate dur­ing cer­tain parts of the year. In habi­tats with abun­dant re­sources cervid home-range size does not change be­tween sea­sons. How­ever, in poor habi­tats win­ter ranges ex­pand sig­nif­i­cantly, pre­sum­ably to off­set the de­crease in for­age qual­ity and abun­dance that oc­curs dur­ing win­ter. Deer are typ­i­cally more ag­gres­sive dur­ing food short­ages, in areas of high pop­u­la­tion den­sity, and dur­ing mat­ing sea­son. They often make them­selves ap­pear more in­tim­i­dat­ing by rais­ing their body hair (i.e., pi­lo­erec­tion) through con­trac­tion of the ar­rec­tor pili mus­cle, which makes them ap­pear larger. (Bauer, 1985; Danilkin, 1996; Ful­bright and Or­tega-S., 2006; Hiller, 1996; Put­nam, 1989; White­head, 1972)

Larger, more ag­gres­sive males tend to gain dom­i­nance over oth­ers, which re­sults in ac­cess to fe­males dur­ing mat­ing sea­son and con­se­quently, higher re­pro­duc­tive rates. Dur­ing male-male com­pe­ti­tion for mates, larger males are dom­i­nant, and if two an­i­mals are the same size, the in­di­vid­ual with the largest set of antlers gains dom­i­nance, un­less the larger in­di­vid­ual is past his prime. In some species, in­di­vid­u­als may en­cir­cle one an­other with a stiff-legged stride while mak­ing a high-pitched whine or low grunt­ing sound and is meant to in­tim­i­date rival in­di­vid­u­als. Dur­ing mat­ing sea­son, male cervids often scrape the ground with their fore­limbs to ad­ver­tise their pres­ence and avail­abil­ity to po­ten­tial mates. Scrapes are usu­ally made by dom­i­nant males and con­sist of a “sign-in”, which in­volves chew­ing on a branches over­hang­ing the scrape, paw­ing the scrape un­der­neath the branch, and rub­bing glan­du­lar se­cre­tions on the scrape, which ad­ver­tises his pres­ence. In some cases, males may uri­nate, ejac­u­late, or defe­cate in the scraped area. Fe­males are most ag­gres­sive when they have off­spring with them. They are very pro­tec­tive of their young and read­ily de­fend their off­spring against both in­ter- and in­traspe­cific threats. (Bauer, 1985; Danilkin, 1996; Ful­bright and Or­tega-S., 2006; Hiller, 1996; Put­nam, 1989; White­head, 1972)

So­cial or­ga­ni­za­tion in cervids is highly vari­able and in some cases is based on sea­son. Al­though most species re­main in small groups, large herds may re­sults dur­ing feed­ing, after which in­di­vid­u­als tend to dis­perse. In gre­gar­i­ous cervids, males join calf-cow herds dur­ing mat­ing sea­son to mate then quickly re­turn to their soli­tary lifestyles. Dur­ing sum­mer, many cervids re­main in small groups with some species be­com­ing soli­tary. Dur­ing win­ter, cervids may con­gre­gate into larger fam­i­lies or herds, which likely helps re­duce vul­ner­a­bil­ity to pre­da­tion. Dom­i­nant in­di­vid­u­als sig­nal their sta­tus in the hi­er­ar­chy with a “hard look”, which in­volves star­ing di­rectly at a po­ten­tial rival while lay­ing their ears back with his or her head low­ered. If the rival in­di­vid­ual is not will­ing to chal­lenge for dom­i­nance, they slowly back away and refuse eye con­tact. If the “hard look” is suc­cess­ful, he or she will drop and ex­tend their head to­ward the sub­or­di­nate in­di­vid­ual, after which a charge may oc­curs. (Bauer, 1985; Danilkin, 1996; Ful­bright and Or­tega-S., 2006; Hiller, 1996; Put­nam, 1989; White­head, 1972)

Sim­i­lar to other en­dother­mic an­i­mals, many cervids mi­grate ac­cord­ing to prox­i­mal cues, such as pho­tope­riod. These prox­i­mal cues serve as in­di­ca­tors for var­i­ous ul­ti­mate fac­tors, such as changes in sea­son, which can af­fect the abun­dance of pests, preda­tors, and for­age. Al­though the costs of mi­gra­tion can be great, ben­e­fits often in­clude in­creased in­di­vid­ual sur­vival rates and in­creased re­pro­duc­tive fit­ness. One of the best-stud­ied cases of cervid mi­gra­tion is that of bar­ren-ground cari­bou, which travel an an­nual dis­tance of more than 500 km. Un­for­tu­nately, sea­sonal mi­gra­tion is cued by pho­tope­riod while onset of plant-grow­ing sea­son is cued by tem­per­a­ture. If the grow­ing sea­son of species-spe­cific re­sources is not pre­cisely matched to the ini­ti­a­tion of mi­gra­tion, changes in plant phe­nolo­gies may detri­men­tally im­pact the long-term sur­vival of mi­gra­tory an­i­mals. For ex­am­ple, in­creas­ing mean spring tem­per­a­tures in West Green­land ap­pear to have re­sulted in a mis­match be­tween cari­bou mi­gra­tory cues and the onset of spring grow­ing sea­son for im­por­tant for­age plants. Ev­i­dence sug­gests that cari­bou mi­gra­tions are not ad­vanc­ing at a com­pa­ra­ble rate with for­age plants and as a re­sult, calf pro­duc­tion in West Green­land cari­bou has de­creased by a fac­tor of four. (Dar­ling, 1937; Feld­hamer, et al., 2007; Nowak, 1999; Post and Forch­ham­mer, 2008; Scott, 1988; Vaughan, et al., 2000)

• Key Behaviors
• cursorial
• terricolous
• diurnal
• crepuscular
• motile
• migratory
• solitary
• territorial
• social
• dominance hierarchies

Com­mu­ni­ca­tion and Per­cep­tion

Cervids use three main types of com­mu­ni­ca­tion: vocal, chem­i­cal, and vi­sual. Vocal com­mu­ni­ca­tion is used pri­mar­ily dur­ing times of fear or ex­cite­ment. The most com­mon form of vocal com­mu­ni­ca­tion is bark­ing, which is typ­i­cally used in re­sponse to a dis­tur­bance, such as vi­sual con­tact with a preda­tor or a dis­turb­ing noise. Bark­ing is also used as an ex­pres­sion of vic­tory after a com­pet­i­tive in­ter­ac­tion be­tween two males. Cervids also com­mu­ni­cate through a va­ri­ety of hor­mone and pheromone sig­nals. For ex­am­ple, male cervids de­mar­cate ter­ri­tory with glan­du­lar se­cre­tions rub­bing their face, head, neck, and sides against trees, shrubs, or tall grasses. Cervids also use vi­sual com­mu­ni­ca­tion, known as scrap­ing. Scrap­ing is pri­mar­ily used dur­ing mat­ing sea­son by males to ad­ver­tise their pres­ence and avail­abil­ity to fe­males. To cre­ate a scape, males paw the ground with the fore­limbs, pro­duc­ing patches of bare ground about 0.5 m to 1.0 m in width. Typ­i­cally, scrapes are marked with a se­cre­tion from the in­ter­dig­i­tal glands lo­cated be­tween their hooves. In re­sponse to a po­ten­tial threat, some species stand with their body tensed and rigid, while lean­ing slightly for­ward, which sig­nals the po­ten­tial threat to con­specifics. (Danilkin, 1996; Hiller, 1996; White­head, 1972)

• Communication Channels
• visual
• acoustic
• chemical

• Other Communication Modes
• pheromones
• scent marks

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

All cervids are ob­lig­ate her­bi­vores with diets in­clud­ing grass, small shrubs, and leaves. In ad­di­tion to the true stom­ach, or abo­ma­sum, cervids have 3 ad­di­tional cham­bers, or false stom­achs, in which bac­te­r­ial fer­men­ta­tion takes place. In ru­mi­nants, the di­ges­tion of high-fiber, poor-qual­ity food oc­curs via four dif­fer­ent path­ways. First, gas­tric fer­men­ta­tion ex­tracts lipids, pro­teins, and car­bo­hy­drates, which are then ab­sorbed and dis­trib­uted through­out the body via the in­testines. Sec­ond, large undi­gested food par­ti­cles form into a bolus, or ball of cud, which is re­gur­gi­tated and re-chewed to help break down the cell wall of in­gested plant ma­te­r­ial. Third, cel­lu­lose di­ges­tion via bac­te­r­ial fer­men­ta­tion re­sults in high ni­tro­gen mi­crobes that are oc­ca­sion­ally flushed into the in­tes­tine, which are sub­se­quently di­gested by their host. These high-ni­tro­gen mi­crobes serve as an im­por­tant pro­tein source. Fi­nally, cervids can store large amounts of for­age in their stom­achs for later di­ges­tion. All cervids chew their cud, have three or four-cham­bered stom­achs, and sup­port mi­croor­gan­isms that break­down cel­lu­lose. Un­like many other ru­mi­nants, cervids se­lec­tively for­age on eas­ily di­gestible veg­e­ta­tion rather than con­sum­ing all avail­able food. (Feld­hamer, et al., 2007; Put­nam, 1989; Van Soest, 1994; Vaughan, et al., 2000; Whitaker and Hamil­ton, 1998)

• Primary Diet
• herbivore
  • folivore
  • lignivore

• Foraging Behavior
• stores or caches food

Pre­da­tion

In areas where large car­ni­vore pop­u­la­tions have not been sig­nif­i­cantly re­duced by hu­mans, pre­da­tion rep­re­sents an im­por­tant cause of mor­tal­ity for cervids. For many species, pre­da­tion is the pri­mary means of con­trol­ling pop­u­la­tion den­si­ties. For many cervids, pre­da­tion on calves is es­pe­cially im­por­tant in lim­it­ing pop­u­la­tion size, and much of this pre­da­tion is ac­com­plished by smaller car­ni­vores (e.g., Canada lynx, cara­cal, and coy­ote). It is dif­fi­cult, how­ever, to es­ti­mate the nat­ural ef­fect of pre­da­tion on cervids, as preda­tor pop­u­la­tions in many lo­ca­tions have been sig­nif­i­cantly re­duced or elim­i­nated by hu­mans. To avoid pre­da­tion, gre­gar­i­ous species for­ag­ing in open habi­tats group to­gether to face po­ten­tial threats. Soli­tary species avoid preda­tors by for­ag­ing in or near the pro­tec­tive cover of wood­land or brush habi­tat. The young of most cervids have spots or stripes on their pelage, which helps cam­ou­flage them in dense veg­e­ta­tion. All species give a harsh bark, which serves as an alarm to con­specifics. Pronk­ing (i.e., con­tin­u­ously jump­ing high into the air) and tail-flar­ing is a known re­sponse to preda­tors at close range, as well as when in­di­vid­u­als are star­tled. Cervids also have acute senses of sight, hear­ing, and smell, which helps them avoid po­ten­tial preda­tors. (Put­nam, 1989)

• Anti-predator Adaptations
• cryptic

• Known Predators

  • Lynx (Lynx canadensis)
  • Caracal (Caracal caracal)
  • Coyote (Canis latrans)
  • Gray wolf (Canis lupus)
  • Grizzly bear (Ursus arctos)
  • Mountain lion (Puma concolor)
  • Jaguar (Panthera onca)
  • Tiger (Panthera tigris)
  • Large Raptors (Falconiformes)
  • Ocelot (Leopardus pardalis)
  • Humans (Homo sapiens)

Ecosys­tem Roles

Cervids are an im­por­tant food source for many preda­tors through­out their ge­o­graphic range. For ex­am­ple, one study showed that over 80% of the feces of gray wolves in Al­go­nquin Park in Canada con­tained the re­mains of white-tailed deer. Cervids are host to a va­ri­ety of en­dopar­a­sites, in­clud­ing par­a­sitic flat­worms (Ces­toda and Trema­toda) and many species of round­worm (Ne­ma­toda) spend at least part of their life­cy­cle in the tis­sues of cervid hosts. Cervids are also vul­ner­a­ble to var­i­ous forms of par­a­sitic arthro­pods in­clud­ing ticks (Ixodoidea), lice (Ph­thi­raptera), mites (Psoroptes and Sar­coptes), keds (Hip­po­bosci­dae), fleas (Siphonaptera), mos­qui­toes (Culi­ci­dae), and flies (Diptera). In ad­di­tion, cervids com­pete with other species for food and other re­sources, which can ef­fec­tu­ally limit both in­ter- and in­traspe­cific pop­u­la­tion growth. (Es­calante and Ayala, 1995; Kutz, et al., 2005; Put­nam, 1989; Whitaker and Hamil­ton, 1998)

Cervids play an in­te­gral role in the struc­ture and func­tion of the ecosys­tems in which they re­side, and some species have been shown to alter the den­sity and com­po­si­tion of local plant com­mu­ni­ties. For ex­am­ple, on Isle Royale Na­tional Park, MI, moose (Alces alces) have been shown to alter the den­sity and com­po­si­tion of for­aged aquatic plant com­mu­ni­ties, and fecal ni­tro­gen trans­ferred from aquatic to ter­res­trial habi­tats via the in­ges­tion of aquatic macro­phytes in­creases ter­res­trial ni­tro­gen avail­abil­ity in sum­mer core areas. For­ag­ing by cervids has been shown to have a sig­nif­i­cant im­pact on plant suc­ces­sion, and plant di­ver­sity is greater in areas sub­jected to for­ag­ing. As a re­sult, for­ag­ing might lead to shifts from one plant com­mu­nity type to an­other (e.g., hard­woods to conifers). In ad­di­tion, mod­er­ate lev­els of for­ag­ing by cervids may in­crease habi­tat suit­abil­ity for con­specifics. For ex­am­ple, lit­ter from for­aged plants de­com­poses more quickly than non-browsed, thus in­creas­ing nu­tri­ent avail­abil­ity to the sur­round­ing plant com­mu­nity. More­over, nu­tri­ent in­puts from urine and feces have been shown to con­tribute to longer stem growth and larger leaves in the sur­round­ing plant com­mu­nity, which are pref­er­en­tially fed upon dur­ing sub­se­quent for­ag­ing bouts. Fi­nally, re­search has shown that the de­com­po­si­tion of cervid car­casses can re­sult in el­e­vated soil macronu­tri­ents and leaf ni­tro­gen for a min­i­mum of two years. (Bowyer, 1997; Bump, J., R. Pe­ter­son, J. Vucetich., et al., 2009; Flana­gan and Van Cleve, 1983; Molvar, et al., 1993; Pas­tor, et al., 1993; Risen­hoover and Maass, 1987)

Al­though cervids can be host to nu­mer­ous species of path­o­genic bac­te­ria and pro­to­zoa, in con­junc­tion with anaer­o­bic fungi, sim­i­lar classes of mi­croor­gan­isms are one of the major rea­sons that cervids are as abun­dant and di­verse as they are today. Bac­te­ria com­prise be­tween 60 and 90% of the mi­cro­bial com­mu­nity pre­sent in the ru­mi­nant's gas­troin­testi­nal (GI) tract and help break down cel­lu­lose. Cil­i­ated pro­to­zoa, which makes up 10 to 40% of the mi­crobe com­mu­nity within the rumen, help break down cel­lu­lose, while also feed­ing on starches, pro­teins and bac­te­ria. The pres­ence of anaer­o­bic fungi in the rumen has only been known since the early 1970's. These fungi make up be­tween 5 to 10% of the rumen's mi­cro­bial abun­dance and are thought to help break down the cell wall of in­gested plant ma­te­r­ial. Bac­te­ria and pro­to­zoa that pass from the upper to the lower re­gions of the GI tract rep­re­sent a sig­nif­i­cant por­tion of the di­etary ni­tro­gen re­quired by their host. (Van Soest, 1994)

• Ecosystem Impact
• disperses seeds

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Hu­mans have a long his­tory of ex­ploit­ing both na­tive and ex­otic deer species, hav­ing hunted them in every ge­o­graphic re­gion in which they occur. They are often hunted for their meat, hides, antlers, vel­vet, and other prod­ucts. As hu­mans began to rely more on agri­cul­ture, their de­pen­dence on deer species as a food source de­creased. How­ever, in areas where cli­mate pro­hibits wide-scale agri­cul­ture, such as in the Arc­tic, deer species such as cari­bou are still re­lied upon for food, cloth­ing, and other re­sources. In the past, cari­bou have even been do­mes­ti­cated by no­madic peo­ples in the high Arc­tic. Today, many cervid species are hunted for sport rather than ne­ces­sity. Sev­eral species have also been do­mes­ti­cated as har­ness an­i­mals, in­clud­ing cari­bou and elk. Fi­nally, cervids play an im­por­tant role in the global eco­tourism move­ment as var­i­ous species of deer are read­ily ob­serv­able through­out much of their na­tive habi­tat. (Put­nam, 1989)

• Positive Impacts
• food
• body parts are source of valuable material
• ecotourism

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Many species of cervid are viewed as agri­cul­tural pests, es­pe­cially in areas where they have be­come over­pop­u­lated due to habi­tat al­ter­ations and lack of nat­ural preda­tors. The ef­fects of deer on crops can be dev­as­tat­ing. Most cervid species are for­est dwellers and as a re­sult, they can cause dam­age to tim­ber by brows­ing, bark-strip­ping, and vel­vet clean­ing. In ad­di­tion, deer-ve­hi­cle col­li­sions re­sult in sig­nif­i­cant harm to the health and per­sonal prop­erty of those in­volved. Many cervids carry dis­eases that can be trans­mit­ted to do­mes­tic live­stock and cer­tain species, in­clud­ing white-tailed deer, elk, and Javan rusa, have been in­tro­duced out­side of their ge­o­graphic ranges, caus­ing sig­nif­i­cant harm to na­tive plant and an­i­mal com­mu­ni­ties. (Put­nam, 1989)

• Negative Impacts
• crop pest
• causes or carries domestic animal disease

Con­ser­va­tion Sta­tus

The IUCN's Red List of Threat­ened Species lists 55 species of Cervi­dae, 2 of which are listed as ex­tinct and 1 is con­sid­ered crit­i­cally en­dan­gered. Of the re­main­ing 52 species, 8 are en­dan­gered, 16 are vul­ner­a­ble, and 17 are listed as "least con­cern". The re­main­ing 10 species are listed as "data de­fi­cient". Many more local deer pop­u­la­tion are on the cusp of ex­tir­pa­tion, which could lead to in­breed­ing in ad­ja­cent pop­u­la­tions. Ac­cord­ing to the IUCN, major threats of ex­tinc­tion for cervids in­cludes over ex­ploita­tion due to hunt­ing, habi­tat loss (e.g., log­ging, con­ver­sion to agri­cul­ture, and land­scape de­vel­op­ment), and re­source com­pe­ti­tion with do­mes­tic and in­va­sive an­i­mals. In ad­di­tion, cli­mate change has begun to con­tract species ranges and forced some species of cervid to move pole­ward. For ex­am­ple, moose, which are an im­por­tant eco­log­i­cal com­po­nent of the bo­real ecosys­tem, are no­to­ri­ously heat in­tol­er­ant and are at the south­ern edge of their cir­cum­po­lar dis­tri­b­u­tion in the north cen­tral United States. Since the mid to late 1980's, de­mo­graphic stud­ies of this species have re­vealed sharp pop­u­la­tion de­clines at its south­ern­most dis­tri­b­u­tion in re­sponse to in­creas­ing tem­per­a­tures. In ad­di­tion, cli­mate change has al­lowed more southerly species to move pole­ward, which in­creases com­pe­ti­tion and dis­ease trans­mis­sion at range in­ter­faces of var­i­ous species (e.g., white-tailed deer and moose). Fi­nally, cervids are an im­por­tant food source for a num­ber of dif­fer­ent car­ni­vores. As cervid pop­u­la­tions de­cline, so too will those an­i­mals that de­pend on them. CITES (the Con­ven­tion on In­ter­na­tional Trade in En­dan­gered Species of Wild Fauna and Flora) lists 25 species of cervid under ap­pen­dix I. (Bauer, 1985; CITES, 2011; Colby, 1966; Feld­hamer, et al., 2007; IUCN, 2010; Lenarz, et al., 2009; Mc­Carthy, et al., 1998; Mur­ray, et al., 2006; Ohtaishi, 1993)

• IUCN Red List [Link]

  Not Evaluated

Con­trib­u­tors

Katie Holmes (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, Jes­sica Jenk­ins (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, Prashanth Ma­halin (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, John Berini (au­thor, ed­i­tor), An­i­mal Di­ver­sity Web Staff, Phil Myers (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

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