Rucervus eldii hainanus (Cervidae, Mammalia), is also called Hainan Eld’s deer.

Protection class

It is an endemic species of Hainan, and a Class I national protected animal. Among 17 deer species in China, the Hainan Eld’s deer is one of the rarest. It is also listed as Endangered (EN) on the IUCN Red List of Threatened Species.

Morphological characteristics

The Hainan Eld’s deer look like sika deer and have reddish brown hair. Male deer have antlers but no obvious spots scattered on the body as sika deer do. However, two stripes of spots can be found on their brown back. As a Hainan Eld’s deer leaps, its body extends to about 160 cm long and its shoulder height is between 104 cm and 110 cm. A deer weighs about 70-130 kg. This species usually has reddish brown or yellowish brown hair. The color of the back is darker, and a longitudinal black brown dorsal stripe can be observed from the neck to the tail base, dotted with white flower-shaped spots on both sides. Each spot is the size of a coin and they are about 3 cm apart. In addition, some white markings are found scattered in the hips. The males have darker hair than the females, especially during the mating season. In late autumn and early winter, the hair of the Hainan Eld’s deer becomes long and thick. The middle of the back is black brown, and white spots that are arranged on each side of the spine tend to diminish and would not be made visible until the next spring. The color on the sides of the body and the external part of the limbs is lighter, while the abdomen and the limbs inside are off-white. The face and the back of the ears are yellowish brown, while the ear rim is black and the inside of the ear is white. The back of the tail is chestnut brown, and the ventral surface is white or light brown.

An adult Hainan Eld’s deer has less noticeable spots in winter, and the body is long and narrow. Its neck and limbs are also elongated. The long hair on the back is not clearly visible. Its main hooves are narrow and pointed while the side hooves are smaller. Females have no antlers. The antlers of males grow forward and then bend slightly upwards, while the axis is initially backward, and then bends up and stretches forward. There are no diverges found under the longitudinal axis, but in fact they grow higher at the upper end of the axis. The axis is connected with the antlers, forming a large arc, almost bent like a bow. The upper end has 3-6 sharp and thin tips of different lengths, differentiating this deer species from sika deer and other deer. The antlers are over 100 cm long and 12-13 cm thick. The tips are more than 78 cm apart, and the antlers are as long as up to 45 cm.

Habitat

The Hainan Eld’s deer mainly inhabit the hilly slopes or flat land below 200m above sea level. The Chinese name, Po Lu, shares the same meaning as flat land in Hainan dialect.

Habits

Behavior

The Hainan Eld’s deer mate in spring and summer and breed in autumn and winter seasons, contrary to what other deer species do. This is because they have adapted themselves to the tropical environment of Hainan Island for long. The Hainan Eld’s deer are not good at defense, but their superior running and jumping abilities ensure that they can survive in the wild. They are social animals, but males with long and large antlers prefer to live alone. They often appear in groups (3-5 female deer and fawns) by the brook, in the grassland of a valley and wet farmland, or in burned areas. Up to 12 individuals are gathered during the rut or in the mating season. They mostly go out for food in the morning and evening, especially after heavy rain. They are able to endure drought and heat. Though often found foraging near the meadows with water, they are not observed to bath in water or mud. It is said that the Hainan Eld’s deer used to forage in daytime or even get close to or mix with herds before they were pushed to the brink of extinction. Human intervention, however, forced them to come out in the morning and at night.

Diet

The main food for the Hainan Eld’s deer is grass and tender foliage, such as Chrysopogon aciculatus, Zornia and Streblus lour., as well as sweet potato leaves, tender rice seedlings and cane seedlings. They particularly like to eat water grass planted by the water or in the swamp. In addition, they often lick saline and alkali soils to supplement minerals and salt their bodies need.

Foraging

The Hainan Eld’s deer have keen senses of sight and hearing. They are fast runners that are especially good at jumping. They are so alert during foraging that they often raise their head to look around for danger in the wild after taking every two or three bites. After a hasty meal, they would soon disappear. Once predators come nearby, the deer will immediately gallop across high trees, bushes or wide brooks, as if they are flying. In the native place where the Hainan Eld’s deer are discovered, another deer species Rusa unicolor are also found. It is believed that the latter likes to bite the antlers of the former, so the two species never share habitat. In fact, Rusa unicolor mainly lives in foothills at higher altitudes, quite different from the habitat of the Hainan Eld’s deer.

Distribution

The Hainan Eld’s deer community mainly lives in Bangxi town in the Baisha Li Autonomous County and Datian Town in Dongfang City.

Reproduction

The Hainan Eld’s deer is a polygamous mammal. Females begin to breed from 2 years old until 10 years old. The rutting season most commonly takes place in winter and early spring, while the breeding period lasts from February to May. Usually, 1-2 fawns are born each year, after a gestation period of about 225-342 days. Calves at birth are weaned within 4-6 months and reach sexual maturity at the age of 2. The fawn is mainly fed by female deer. Male deer seldom nurse their young even though they live in a group.