DEER (CERVIDS): CHARACTERISTIC, BEHAVIOR, REPRODUCTION

DEER FAMILY


Cervids (clockwise from top left): 1) red deer, 2) fallow deer, 3) southern Pudu, 4) Daguet gris, 5) Tule elk, 6) white-tailed deer; (in the middle) barasingha(top), ) reindeer (bottom)

The deer family includes deer, reindeer and elk. The largest deer are moose, which can weigh nearly a ton, and the smallest is the Chilean pudu, which is not much larger than a rabbit. Deer belong to the family “Cervidae”, which is part of the order “Artiodactyla” (even-toed hoofed mammals). “Cervidae” are similar to “Bovidae” (cattle, antelopes, sheep and goat) in that they chew the cud but differ in that have solid horns that are shed periodically (“Bovidae” have hollow ones).

A male deer is called a buck or stag. A female is called a doe. Young are called fawns. A group is called a herd. Deer don't hibernate and sometimes group together to stay warm. Particularly cold winters sometimes kill deer outright, mainly by robbing them of food, especially when a hard layer of ice and snow keeps them from getting at food.

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). According to Animal Diversity Web: 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 nine to 816 kilograms (20 to 1800 pounds), 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 percent larger than their female counterparts. [Source: Katie Holmes; Jessica Jenkins; Prashanth Mahalin; John Berini, Animal Diversity Web (ADW) /=]

Cervids have a large number of morphological Synapomorphies (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. 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). /=\

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 six introduced species of deer in Australia and New Zealand that have been established since the mid 1800s.

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. /=\

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.

Deer History and Taxonomy

As is the case with many families within the order Artiodactyla, a well-supported history and taxonomy 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 three subfamilies, Hydropotinae, Cervinae, and Odocoileinae. [Source: Katie Holmes; Jessica Jenkins; Prashanth Mahalin; John Berini, Animal Diversity Web (ADW) /=]


Megaloceros giganteus (prehistoric Irish Elk)

It is believed ancestral deer were small, solitary, selective browsers of dense forests; more recent species are larger, more gregarious, grazers of open woodlands. According to Animal Diversity Web: 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 three 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. /=\

All extinct and living deer are thought to have evolved during the Miocene Period (23 million to 5.3 million years ago) and early Pliocene Period (5.4 million to 2.4 million years ago) from a Eurasian ancestor known as protodeer (Dicroceridae). The first true cervids appeared about 20 million years ago during the Early Miocene (23 million to 16 million years ago), 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 Period (5.4 million to 2.4 million years ago). Some Pleistocene Period (2.6 million to 11,700 years ago) 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 meters and a weight around 45 kilograms. In North America, the giant stag moose had tripalmate antlers that spanned almost five 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 (characteristics found in an ancestral species and shared by their evolutionary descendants) 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. /=\

Artiodactyls (Even-Toed Ungulates)

Deer are Artiodactyls. Artiodactyls are the most diverse, large, terrestrial mammals alive today. According to Animal Diversity Web: They are the fifth largest order of mammals, consisting of 10 families, 80 genera, and approximately 210 species. As would be expected in such a diverse group, artiodactyls exhibit exceptional variation in body size and structure. Body mass ranges from 4000 kilograms in hippos to two kilograms in lesser Malay mouse deer. Height ranges from five meters in giraffes to 23 centimeters in lesser Malay mouse deer. [Source: Erika Etnyre; Jenna Lande; Alison Mckenna; John Berini, Animal Diversity Web (ADW) /=]

Artiodactyls are paraxonic, that is, the plane of symmetry of each foot passes between the third and fourth digits. In all species, the number of digits is reduced by the loss of the first digit (i.e., thumb), and many species have second and fifth digits that are reduced in size. The third and fourth digits, however, remain large and bear weight in all artiodactyls. This pattern has earned them their name, Artiodactyla, which means "even-toed". In contrast, the plane of symmetry in perissodactyls (i.e., odd-toed ungulates) runs down the third toe. The most extreme toe reduction in artiodactyls, living or extinct, can be seen in antelope and deer, which have just two functional (weight-bearing) digits on each foot. In these animals, the third and fourth metapodials fuse, partially or completely, to form a single bone called a cannon bone. In the hind limb of these species, the bones of the ankle are also reduced in number, and the astragalus becomes the main weight-bearing bone. These traits are probably adaptations for running fast and efficiently. /=\

Artiodactyls are divided into three suborders. Suiformes includes the suids, tayassuids and hippos, including a number of extinct families. These animals do not ruminate (chew their cud) and their stomachs may be simple and one-chambered or have up to three chambers. Their feet are usually 4-toed (but at least slightly paraxonic). They have bunodont cheek teeth, and canines are present and tusk-like. The suborder Tylopoda contains a single living family, Camelidae. Modern tylopods have a 3-chambered, ruminating stomach. Their third and fourth metapodials are fused near the body but separate distally, forming a Y-shaped cannon bone. The navicular and cuboid bones of the ankle are not fused, a primitive condition that separates tylopods from the third suborder, Ruminantia. This last suborder includes the families Tragulidae, Giraffidae, Cervidae, Moschidae, Antilocapridae, and Bovidae, as well as a number of extinct groups. In addition to having fused naviculars and cuboids, this suborder is characterized by a series of traits including missing upper incisors, often (but not always) reduced or absent upper canines, selenodont cheek teeth, a three or 4-chambered stomach, and third and fourth metapodials that are often partially or completely fused. /=\

Deer Characteristics


deer tails (left to right): 1) white-tailed deer, 2) Mule deer, 3) black-tailed deer, 4) elk, 5) red deer

There is a great deal of physical diversity within the family Cervidae. According to Animal Diversity Web: Typically members have compact torsos and very powerful elongated legs that are well suited for woody or rocky terrain. 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. [Source: Katie Holmes; Jessica Jenkins; Prashanth Mahalin; John Berini, Animal Diversity Web (ADW) /=]

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.

Some deer have hairs that stand erect and give off distinctive and strong odors. The top speed of a deer is around 30 miles per hour. Some deer can reach speeds of 40mph for short bursts and gallop for three or four hours at a speed of 25mph. Some deer can vertically jump 25 feet. The tracks of stags are bigger and broader than those of does. They have a more swaggering walk.

Deer Antlers

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. Many deer annually grow new antlers in the spring and shed their old ones in the fall. The antlers of some species are covered by "velvet" (soft skin laced with blood vessels and covered with fine hair), which provided the antlers with calcium and other nutrients from the body. The antlers reach full growth and peak hardness in the early fall. After this the blood supply to the velvet is cut off. The velvet is rubbed off on bushes and trees in August after the summer.

Antlers are a kind of symbol of strength and virility intended to impress females and intimidate rivals. They are used by males to battle one another in the rutting (mating season). After the rutting season is over in the fall, the antlers fall off. Except for reindeer and caribou, only males grow antlers. Males usually grow spike like antlers when they are two and develop a full rack when they are full grown are age six.

According to Animal Diversity Web: 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. [Source: Katie Holmes; Jessica Jenkins; Prashanth Mahalin; John Berini, Animal Diversity Web (ADW) /=]

Deer Food and Eating Behavior


Antler phylogenetics

All cervids are obligate (eat plants or plants parts), herbivores with diets including grass, small shrubs, and leaves. Some are also classified as folivores (eat mainly leaves) or lignivores (eat wood). All cervids chew their cud, have three or four-chambered stomachs, and support microorganisms that breakdown cellulose. In addition to the true stomach, or abomasum, cervids have three additional chambers, or false stomachs, in which bacterial fermentation takes place. Unlike many other ruminants, cervids selectively forage on easily digestible vegetation rather than consuming all available food. Some cervids store or cache food in their bodies.[Source: Katie Holmes; Jessica Jenkins; Prashanth Mahalin; John Berini, Animal Diversity Web (ADW) /=]

According to Animal Diversity Web: In ruminants, the digestion of high-fiber, poor-quality food occurs via four different pathways. 1) Gastric fermentation extracts lipids, proteins, and carbohydrates, which are then absorbed and distributed throughout the body via the intestines. 2) 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. 3) 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. 4) cervids can store large amounts of forage in their stomachs for later digestion.

Ruminants

Cattle, sheep, goats, yaks, buffalo, deer, antelopes, giraffes, and their relatives are ruminants — cud-chewing mammals that have a distinctive digestive system designed to obtain nutrients from large amounts of nutrient-poor grass. Ruminants evolved about 20 million years ago in North America and migrated from there to Europe and Asia and to a lesser extent South America, where they never became widespread.

As ruminants evolved they rose up on their toes and developed long legs. Their side toes shrunk while their central toes strengthened and the nails developed into hooves, which are extremely durable and excellent shock absorbers.

Ruminants helped grasslands remain as grasslands and thus kept themselves adequately suppled with food. Grasses can withstand the heavy trampling of ruminants while young tree seedlings can not. The changing rain conditions of many grasslands has meant that the grass sprouts seasonally in different places and animals often make long journeys to find pastures. The ruminants hooves and large size allows them to make the journeys.

Describing a descendant of the first ruminates, David Attenborough wrote: deer move through the forest browsing in an unhurried confident way. In contrast the chevrotain feed quickly, collecting fallen fruit and leaves from low bushes and digest them immediately. They then retire to a secluded hiding place and then use a technique that, it seems, they were the first to pioneer. They ruminate. Clumps of their hastly gathered meals are retrieved from a front compartment in their stomach where they had been stored and brought back up the throat to be given a second more intensive chewing with the back teeth. With that done, the chevrotain swallows the lump again. This time it continues through the first chamber of the stomach and into a second where it is fermented into a broth. It is a technique that today is used by many species of grazing mammals.

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.

Ruminant Stomachs


Ruminant stomach

Ruminants chew a cud and have unique stomachs with four sections. They do no digest food as we do, with enzymes in the stomach breaking down the food into proteins, carbohydrates and fats that are absorbed in the intestines. Instead plant compounds are broken down into usable compounds by fermentation, mostly with bacteria transmitted from mother to young.

The cub-chewing process begins when an animal half chews its food (mostly grass) just enough to swallow it. The food goes into the first stomach called the rumen, where the food is softened with special liquids and the cellulose in the plant material is broken down by bacteria and protozoa.

After several hours, the half-digested plant material is separated into lumps by a muscular pouch alongside the rumen. Each lump, or cud, is regurgitated, one at a time and animal chews the cud thoroughly and then swallow it again. This is referred to a chewing the cud.

When the food is swallowed for the second time it by passes through the first two chambers and arrives at the third chamber, the "true" stomach, where and it is digested. As the chewed food moves through this chamber microbes multiply and produce fatty acids that provide energy and use nitrogen in the food to synthesize protein that eventually becomes amino acids. Vitamins, amino acids and nutrients created through chemical recombination then move in the intestine and pass through linings in the gut into the bloodstream.

Deer Behavior

Deer are cursorial (with limbs adapted to running), terricolous (live on the ground), diurnal (active during the daytime), crepuscular (active at dawn and dusk), motile (move around as opposed to being stationary), migratory (make seasonal movements between regions, such as between breeding and wintering grounds), solitary, territorial (defend an area within the home range), social (associates with others of its species; forms social groups), and have dominance hierarchies (ranking systems or pecking orders among members of a long-term social group, where dominance status affects access to resources or mates). [Source: Katie Holmes; Jessica Jenkins; Prashanth Mahalin; John Berini, Animal Diversity Web (ADW) /=]

According to Animal Diversity Web: Although active throughout most of the day, cervids are typically classified as crepuscular (active at dawn and dusk). 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. 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. /=\

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. /=\

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. /=\

Similar to other endothermic (use their metabolism to generate heat and regulate body temperature independent of the temperatures around them), 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 kilometers. 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 (make seasonal movements between regions, such as between breeding and wintering grounds), animals. For example, increasing mean spring temperatures in West Greenland appear to have resulted in a mismatch between caribou migratory (make seasonal movements between regions, such as between breeding and wintering grounds), 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. /=\

Deer Senses and Communication

Deer sense using vision, touch, sound and chemicals usually detected with smell and communicate with vision, sound and chemicals usually detected by smelling. They also employ pheromones (chemicals released into air or water that are detected by and responded to by other animals of the same species) and scent marks produced by special glands and placed so others can smell and taste them. [Source: Katie Holmes; Jessica Jenkins; Prashanth Mahalin; John Berini, Animal Diversity Web (ADW) /=]

According to Animal Diversity Web: 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 meters to 1.0 meters 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 members of their own species. /=\

Deer Mating and Reproduction

Normally-placid bucks become fierce warriors during the rutting (mating season). Their eyes become bloodshot, their necks puff out and they charge any threat with antlers down. Battling bucks run head on into one another with their antlers and keep charging until one backs off. Sometimes two bucks become locked up and die together. Scientist have been able to make a female red deer go into heat by playing a recording of a male red deer's mating roar. Deer fawns have dappled coats that match the broken light of the woodland floor.

According to Animal Diversity Web: 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. [Source: Katie Holmes; Jessica Jenkins; Prashanth Mahalin; John Berini, Animal Diversity Web (ADW) /=]

Most male cervids cast their antlers regularly and do not mate again until their antlers are hard, which results in a regular birthing pattern, given that mating only occurs during certain months. 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. 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.

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. /=\

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.

Roe deer are the only cervid known to have delayed implantation (a condition in which a fertilized egg reaches the uterus but delays its implantation in the uterine lining, sometimes for several months). Cervids typically have from one to three 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.

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.

Deer Offspring and Parenting

Deer are iteroparous. This means that offspring are produced in groups such as litters multiple times in successive annual or seasonal cycles. 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. Age at weaning varies among species, with smaller species nursing for only two to three months and larger species nursing for much longer. For example Bornean yellow muntjacs are weaned by about two months of age and North American moose are weaned by about five months, however, erratic nursing may continue for up to seven months after birth. [Source: Katie Holmes; Jessica Jenkins; Prashanth Mahalin; John Berini, Animal Diversity Web (ADW) /=]

Parental care is provided by females. Pre-birth, pre-weaning and pre-independence provisioning and protecting are done by females. The post-independence period is characterized by the association of offspring with their parents. According to Animal Diversity Web: 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. /=\

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. /=\

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 seven 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. /=\

Predators of Deer

Deer are hunted by humans and are prey of large carnivores such as tigers, cougars, wolves and occasionally bears. Deer meat is called venison. People have made buckskin jackets, moccasins and other items of clothing from deer hide.

Known Predators of deer include lynxes, caracals, coyotes, gray wolves, grizzly bears, mountain lionss, jaguars, tigers, large raptors, ocelots, and humans. According to Animal Diversity Web: In areas where large carnivores (mainly eat meat or animal parts), 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. [Source: Katie Holmes; Jessica Jenkins; Prashanth Mahalin; John Berini, Animal Diversity Web (ADW) /=]

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 fur, which helps camouflage them in dense vegetation. All species give a harsh bark, which serves as an alarm to members of their own species. 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. /=\

Ecosystem Roles of Deer

Cervids are an important food source for many predators throughout their geographic range. For example, one study showed that over 80 percent 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. /=\

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 members of their own species. 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. /=\

Deer, Humans and Conservation

Humans have utilize deer for food and skins. Their body parts are source of valuable material. They are an ecotourism draw. According to Animal Diversity Web: 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 (move from place to place, generally within a well-defined range), 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. [Source: Katie Holmes; Jessica Jenkins; Prashanth Mahalin; John Berini, Animal Diversity Web (ADW) /=]

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. /=\

The IUCN's Red List of Threatened Species lists 55 species of Cervidae, two of which are listed as extinct and one is considered critically endangered. Of the remaining 52 species, eight 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. /=\

Deer in Europe and Northern Asia

There are three main species of deer found in Europe and western Asia: 1) red deer; 2) roe deer; and 3) fallow deer. Fallow deer are found in southern Europe and northern Africa. They stand about three feet at the shoulder, and have a white-spotted summer coat and flat gooselike antlers.

Red deer were featured in the Robin Hood stories. Ranging across Europe as far east as Iran and as far south as northern Africa, they are distinguished by a long fringe of hair at the animal's throat. The hart (stag) stands about four feet tall at the shoulder and has spectacular many-pointed antlers. They fight fiercely and roar in the rutting season. They let out booming bellowing roars—as often as 3,000 times a day—to lure females. Their defensive calls often attracts unhitched females.

Roe deer have long been a favorite of hunters. They range from Britain across the length of Russia and Asia to the Pacific Ocean. Males stand two feet tall at the shoulder are known for making circular trails called "doe rings" when they pursue females in the mating season.

The highest concentration of large deer species in temperate Asia occurs in the mixed deciduous forests, mountain coniferous forests, and taiga bordering North Korea, Manchuria (Northeastern China), and the Ussuri Region (Russia). These are among some of the richest deciduous and coniferous forests in the world where one can find Siberian roe deer, sika deer, elk, and moose. Asian caribou occupy the northern fringes of this region along the Sino-Russian border. Deer such as the sika deer, Thorold's deer, Central Asian red deer, and elk have historically been farmed for their antlers by Han Chinese, Turkic peoples, Tungusic peoples, Mongolians, and Koreans.

Sika deer are a forest deer deer found in East Asia from Siberia south through China to Vietnam and Taiwan to the south and Japan to the east. These deer are divided into more than a dozen different regional subspecies, of which seven are found in Japan. The largest is the ezo-jika, which lives in Hokkaido. Sika are browsers that live primarily in forests — but are often seen roaming around farmland — and feed on tree leaves, fruits, flowers, buds, acorns and nuts. They have large eyes and a strange haunting whistle. Adults can have large stately antlers. White hairs on the rumps can flare out like chrysanthemums when the animals are excited.

Image Sources: Wikimedia Commons

Text Sources: Animal Diversity Web animaldiversity.org ; National Geographic, Live Science, Natural History magazine, David Attenborough books, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Discover magazine, The New Yorker, Time, Reuters, Associated Press, AFP, Lonely Planet Guides, Wikipedia, The Guardian, Top Secret Animal Attack Files website and various books and other publications.

Last updated January 2025


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