Rucervus eldii
Eld's deer

Eld's deer (Rucervus eldii) are indigenous to Southeast Asia. They were discovered in the Manipur Valley of India in 1838 by Lieutenant Percy Eld. Three recognized subspecies of R. eldii exist today. They are Rucervus eldii eldii in Manipur, Rucervus eldii thamin, previously in Burma/Myanmar and the Malay Peninsula, and Rucervus eldii siamensis, in Thailand, Annam, and Hainan island. The subspecies Rucervus eldii thamin is now restricted to Burma/Myanmar. Rucervus eldii siamensis is found throughout Hainan island . Some individuals of R. eldii live as far north as 48°N. Eld's deer have also been documented in Cambodia, Laos, and Vietnam. (McCracken, 1996; McShea et al., 1999; Monfort et al., 1990; Wildt and Wemmer, 1999; Yan Ling, 1996)

The main habitat for Eld's deer is referred to as an indaing forest and is usually dominated by the tree Dipterocarpus tuberculatus. Indaing refers to sandy, flat terrain that floods seasonally. The range of Eld's deer also includes monsoonal forest. Rucervus eldii thamin is found in a variety of habitats, ranging from dry scrub and thorn forest to open deciduous forest. There are three main types of deciduous forests in southeastern Asia: dipterocarp (indaing), dry (thandahat), and mixed (teak). All three of these receive between 100 and 200 cm of rainfall a year. (Aung et al., 2001; Bronson, 1989; McShea et al., 1999; McShea et al., 2001; Prescott, 1987)

The ability of Eld's deer to obtain adequate amounts of nutrients to sustain both the bone growth and body mass of males, and the gestation and lactation needs of females, depends heavily on the types and abundances of food sources in the habitat. Rucervus eldii exhibits seasonal movements that are slightly correlated with crop cycles. They tend to wander farther from crop land during the hot-dry season, mainly because they are moving closer to existing water holes. (McShea et al., 1999; McShea et al., 2001; Prescott, 1987)

Adults weigh between 70 and 130 kg. Eld's deer have selenodont teeth, a large body and foregut fermentation type of digestion. (Aung et al., 2001; McCracken, 1996; McShea et al., 2001; Prescott, 1987)

Eld's deer, like many other cervids, have a reddish brown to gray colored coat. They are similar in size to white-tailed deer, but differ somewhat in appearance. They have uniquely shaped antlers that are replaced every year. The antlers of Eld's deer are shaped in one continuous curve from the pedicle on the head to the very tip of the antler. There is a lesser branch of the antler that is positioned directly off the pedicel that grows in the direction of the front of the head. (McCracken, 1996; McShea et al., 2001; Prescott, 1987)

The maximum recorded longevity of a R. e. siamensis male in captivity is 14 years and 11 months. Females can live up to 19 years and 7 months in captivity. (Prescott, 1987)

Rucervus eldii is mainly nocturnal and crepuscular. Males tend to be loners throughout most of the year, except in the spring when mating begins. Females tend to remain in close association with their fawns and other female-fawn pairs. Large groups are often formed when males join these groups of females before the breeding season begins. Groups of 1 to 20 animals are common, and usually have a male to female ratio of 1:1.59, and a doe to fawn ration of 1:0.54. Group sizes peak in April and begin to slowly decrease through September. (Aung et al., 2001; McCracken, 1996)

Rucervus eldii is reported to have both daily and seasonal migrations. These movements are largely influenced by breeding times and differences in availability of food and water in the various seasons. (Aung et al., 2001; McCracken, 1996)

In captive populations, Eld's deer are known to be very excitable. They often become alarmed at the smallest disturbance and will run around frantically intheir enclosures, sometimes bumping into everything in their path. (Aung et al., 2001; McCracken, 1996)

Home Range

The home range for these animals varies from 3.8 to 14.71 square km.

Most cervids have numerous glands on their feet, legs, and faces. These scent glands are used for intraspecific communication. Males often use chemosignaling through urine and feces to inform females that they are in reproductive condition. Not only do cervids utilize chemosignaling, they also use sight and touch. This is mostly commonly displayed before breeding when their antlers are at their largest. Rucervus eldii does not use combat as its primary mode of hierarchy, but it is sometimes necessary to fend off a competing male. (Aung et al., 2001; Hosack et al., 1998)

Rucervus eldii is a species known to graze and browse opportunistically on wild fruits and cultivated crops from nearby fields. A few commonly eaten crops are rice, lentils, maize, peas and rape. Rucervus eldii thamin tends to eat the fruits of various woody species such as Emblica officinalis, Terminalia chebula, and Diospyrous burmanica. They also eat forbs and grasses in these areas. (Aung et al., 2001; McShea et al., 2001; Monfort et al., 1990)

Rucervus eldii is closely associated with areas that are seasonally burned. These deer eat the new grasses as they emerge after the burn. (Aung et al., 2001; McShea et al., 2001; Monfort et al., 1990)

Feeding may vary seasonally, not just with food availability, but with reproductive considerations. During rut males, experience a decline in body weight. This is proably due to a decrease in their food intake. (Aung et al., 2001; McShea et al., 2001; Monfort et al., 1990)

All cervids are foregut fermentators. This means that they have four-chambered stomachs, and are able to extract the majority of the nutrients offered by their poor quality food source. (Aung et al., 2001; McShea et al., 2001; Monfort et al., 1990)

One anti-predator adaptation of R. eldii is periodically forming large groups or herds, even though these deer are usually solitary creatures. Large groups decrease the risk of predation, both by increasing the chance that a predator will kill a neighboring animals rather than a lone individual, and by the increased vigilance for predators which can be provided by all members of the group. (Aung et al., 2001)

The most common predators of R. eldii are tigers, leopards, and dholes. But only the latter two predators still exist in abundant numbers in the present range of this deer. Jackals and occasionally feral dogs also hunt R. eldii. Poaching by humans is a serious problem to Eld's deer populations. (Aung et al., 2001)

Rucervus eldii plays an important role in dispersing seeds due to its dependence upon fruit as a food source. This species is probably also important in structuring plant communities as a result of its browsing behavior. (Aung et al., 2001; McShea et al., 2001)

Rucervus eldii is known to feed heavily on the cultivated crops of the local farmers. These deer are a major destroyer of crops, and are considered by locals to be a significant agricultural problem. (Aung et al., 2001)

Eld's deer are hunted as game animals and are used as a food source. They are prized as a game animal because of their antlers and hides. There have been cases when these deer have been used for "traditional" medicinal products. Oftentimes, Els's deer are poached for this purpose. In addition to these destructive uses, Eld's deer have become a major zoo animal, especially since their populations are decreasing in the wild. (McCracken, 1996; McShea et al., 1999)

All three subspecies of R. eldii have become threatened. Conservation of these deer in tropical regions is difficult because of the fragmentation of their forest home caused by farming. These deer are a targer for poaching, as they can be used for food, trophies, and "traditional" medicinal products. The increase of the human population within the range of this species puts a additional stress upon these animals. There is a lack of funding for protection.

One of the subspecies, R. e. eldii, has become so rare that survival will eventually rely on the practice of gene exchange of the wild and captive organisms by means of assisted reproduction. This type of assisted breeding is being used in Thailand and Burma/Myanmar on the other subspecies as well.

Poaching reduced the R. e. siamensis population from a reported 500 individuals in 1964, to 26 in 1976. Hainan Datian Nature Reserve was established to help R. e. siamensis recover, and the population increased to 151 individuals by 1986. (McCracken, 1996; McShea et al., 1999; Prescott, 1987; Wildt and Wemmer, 1999; Yan Ling, 1996)

Eld's deer are sometimes refered to as brow-antlered deer. They were previously considered a member of the genus Cervus as Cervus eldi or Cervus eldii. (Prescott, 1987)