Current status, distribution and conservation of the Sri Lankan Hog Deer Hyelaphus porcinus (Zimmermann, 1780) (Cetartiodactyla: Cervidae)

1,2,3 Biodiversity Education And Research (BEAR), No 4, Dr. E.W. Adikaram Mawatha, Pitakotte, Sri Lanka 1 Young Biologist’s Association, National Museum of Natural History, Sir Marcus Fernando Mawatha Colombo 7, Sri Lanka 1 Centre for Environment Education Sri Lanka (CEESL) 2 Department of Zoology,University of Kelaniya, Kelaniya, Sri Lanka 5 Postgraduate Institute of Science (PGIS), University of Peradeniya, Peradeniya, Sri Lanka 6 Department of Biology and Ecology, Faculty of Medicine, South Asian Institute of Technology and Medicine (SAITM), Malabe, Sri Lanka 1 nilanthavishvanath@yahoo.com,2 ranil_n@hotmail.com, 3 Jayampathi_herath@yahoo.com (corresponding author)


INTRODUCTION
Hyelaphus porcinus (Zimmermann, 1780) commonly known as Hog Deer or Paddy-field Deer is a mediumsized ungulate which belongs to the family Cervidae. Keelart in 1852 described the Hog Deer as a taxon unique to Sri Lanka and called it Axis oryzus. Pocock (1943) synoymised this taxon as a subspecies under Axis porcinus Zimmermann, 1780. This is further justified by recent research carried out on the species by the authors and co-worker that this species is indeed a unique species to Sri Lanka (C.S.R. Nanayakkara pers. comm. 2011). It was thought that the Hog Deer was introduced to Sri Lanka. However, it has not been documented in literature, while every product of commerce and alien species brought into Sri Lanka was documented (C.S.R. Nanayakkara pers. comm. 2011). Literature and records dating back to almost 400 years were referred and although many species of flora and fauna were taken out none was brought in at the time. None of it indicates that the Hog Deer was introduced to Sri Lanka. Incidentally there is a record of the Hog Deer being exported to Australia from Sri Lanka Yapa & Ratnavira (2013). It is counted as one among the smallest deer species in the world and also regarded as one of the most primitive species of deer. As a species the Hog Deer has some peculiar characteristics, the body being long and the legs relatively short. The adult Hog Deer reaches a shoulder height of approximately 60cm with a dark brown pelage, often with white tips giving a speckled appearance. Whereas the juveniles bear white spots which they lose as they mature, males possess backward pointing antlers that reach approximately 30-35 cm in length. The "Hog Deer" is named so, because of its unique way of running; the head is hung low, like that of a hog while the animal runs, which helps the animal in ducking obstacles in its way rather than leaping over them (Anonymous 2005).
It has a wide distribution in the Asian region from Pakistan to India, Bangladesh, Nepal, Bhutan, Burma, Thailand, Vietnam and Sri Lanka where it inhabits grasslands, riverine forests and coastal areas and a well-documented introduced population is found in Victoria, Australia (Phillips 1935). The Hog Deer is a rare and shy animal which is nocturnal in habit and is only found in the wet zone of the island. It inhabits a narrow stretch of the coastal belt in the southwestern part of the island from Kalutara to Galle, stretching inland for 20-30 km (Phillips 1935). It was particularly common in the marshes round the Ambalangoda, Telwatte and Matugama area and along the Bentota River. However, after the 1930s there is a dearth of records on the Hog Deer. Due to habitat destruction and hunting taking its toll on this species it was considered that the species had become extinct in the wild by some researchers in the early 1970s. However, there were sporadic records of this species from cinnamon plantations in the Galle District and the subsequent study in 1992 by McCarthy & Dissanayake (1994) gave a consensus to the exact status and distribution of this cervid. It was found to inhabit a 35km 2 triangular region in between Elpitiya, Induruwa and Ambalangoda (Fig. 1).
According to the IUCN Red list of 2007 which was compiled by the IUCN Sri Lanka and the Ministry of Environment and Natural Resources, the Hog Deer in Sri Lanka is an endangered species due to the decline in extent of occurrence, area of occupancy, area extent and or habitat quality and decline in population size. Yet, there is a dearth of information on the ecology and the area of occupancy, which remained unclear for several years. The present study was carried out for a period of one year from March 2009 to March 2010 to assess the current distribution and status of the nominated species to support their in situ conservation management. Hiniduma forest reserves where Hog Deer were totally absent. On the other hand the hoof print of Hog Deer can be set apart from other hoof prints of ungulates due to its medium size as well as the gap between the two hoofs. It is highly adapted for walking or running on muddy terrain, whilst running the hoofs become erected. The more commonly seen tracks were that of Wild Boar Sus scrofa, whose tracks can be differentiated from Hog Deer tracks by its blunt end and much rounded shape. During the course of the study a small herd of Spotted Deer Axis axis ceylonensis was recorded in the designated area of study. This herd had once been kept in a plantation as domestic animals, but later on due to certain restriction the herd had been released to the wild. Because the hoof print of the Spotted Deer is much larger than that of the Hog Deer and the hoof print of Spotted Deer fawns can be set apart from the Hog Deer, as the gap in each hoof is wider in the Hog Deer, as such it did not by anyway hinder the research.

Pellet groups evaluation
Evaluation of pellet/dung piles is another well accepted method for identifying different species of deer , but it could be a bit confusing if domestic grazing animals such as goats are present, as their dung piles are similar to that of Hog Deer. Since the goats were present only near human settlements there was only a slight chance of confusion. The size of the pellets and number of pellets depends on the age and size of the animal. Smaller individuals drop small pellets and it consists of about 45-60 pellets in one cluster. Compared to the size of the animal, Hog Deer have much larger pellets than that of the Barking Deer, but much smaller than that of the Sambar Rusa unicolor and Spotted Deer Axis axis ceylonensis.

Crop damage evaluation
If crops such as paddy, cinnamon, yams and vegetables are frequently damaged at night, it is a good sign that there is a species of deer in the vicinity. Hog Deer prefer to feed on the tender shoots of paddy and saplings and shoots of cinnamon and also various types of vegetables. This damage is evident even after several months in cinnamon plants as the plants become bushy due to the apical shoot being damaged.

Information gathering from local people
Randomly selected villagers from the survey area were interviewed using an open ended questionnaire and a photographic guide of the species of deer found in Sri Lanka was used for the identification of the species. The interviewees were from different walks of life such as Buddhist monks, farmers, land owners, plantation workers (cinnamon and tea), fishermen, hunters (poachers), caretaker (plantation), boatmen and sand miners. Thus, a total of 356 people in 52 villages spanning the entire area of study were interviewed.

Conducting awareness programs
Awareness programs were conducted using posters as well as delivering lectures whenever possible for school children, farmers and social workers in identified areas especially in areas where relic populations of Hog Deer were found.

RESULTS
The present study granted a similar value to direct sightings and indirect signs, and could enumerate a total of 23 confirmed Hog Deer occurrence sites in an area that lies within two major river basins namely Bentota and Gin, covering an area of approximately 220km 2 in the wet zone of the island. Figure 3 is the map of the area surveyed showing the current distribution range of the Hog Deer in Sri Lanka. Its northern most point (6 0 23'187"N & 80 0 08'570"E) is a village called Katuwatta in Miriswatta an area 5km inland from the coastal belt whereas the southernmost point (6 0 09'150"N & 80 0 08'570"E) is 3km south of Gonapinuwala Town. The eastern most points were Wathurawila Arannya Kanda, a rain forest patch about 18km inland from the coastal belt and a cinnamon plantation named Omatta kurudu watta 16km inland from the coastal belt. The western border lies about 3-7 km inland and parallel to the coastal belt.
During the questionnaire survey with local inhabitants, two records of the Hog Deer occurring outside the Benthara River basin from Udugama and Yagirala remained unconfirmed, and further evidence is needed to confirm the occurrence in these areas, as it does not compute with the documented distribution of the species. Through the interview survey with local inhabitants, 23 locations out of 53 were identified as possible sites of Hog Deer occurrence, out of which seven were confirmed by the authors, as to the presence of Hog Deer through field observations such as deer tracks (Images 1-3), crop damage (Images 4-5) and dung piles (Images 6-8). In addition two sets of antlers and nine captive animals (two bucks, three females and four fawns) were also recorded from the area surveyed (Image 9).
There are a number of threats, which affect the However, it is essential to study the density, home range and other ecological aspects in order to get a precise consensus of the population status. It was also noted, that the male Hog Deer were rarely encountered, during the whole survey only one male was met with, it could be due to the fact that since males lead a solitary life and only form herds during the rutting season (Prasanai et al. 2012) or perhaps they are hunted for their antlers. Given the elusiveness of the species it is very difficult to carry out a census of the population. Despite all, it is clear that several relic populations of Hog Deer inhabit the Bentota and Gin River catchment areas.
Despite being a protected species under the fauna and flora protection ordinance revised Act No.22 of 2009, the illegal killing of these animals continue. The people have several methods of hunting them: one is by night using flash lights, where when the flash light is flashed at the animal it stops in its path and stares at the light making it easy to be shot; the other method is administrated during the day, by using dogs and beaters, where likely forest patches that Hog Deer might be found lying up for the day are disturbed using beaters and when the deer take flight the dogs are set on them and once the animal is cornered it is killed by people. Hog Deer also fall victim to snares and pit fall traps, which are set up for other animals such as wild boar, porcupines this type of hunting has also been highlighted by Philips Image 9. Hog Deer which was kept in Atorawa temple situated in Galle District (1935). However, some animals escape with injuries during the ordeal, hence the high number of animals found with broken legs, damaged ribs during the survey. The victims of this type of hunting are mainly females and fawns as they are found congregating in small herds, and also the villagers tend to target young animals to mature ones as the flesh of the young animals is supposed to be a delicacy (Table 1).
During the survey nine animals were seen in captivity, in places such as monasteries and hermitages, this could have a dire effect on the species as they could interbreed with other species of deer, having a negative effect on their gene pool. Phillips (1935) stresses the fact, that in India this species has interbred with Spotted Deer and have borne fertile young, so if the individuals which are held in captivity do happen to interbreed with Axis Deer, this will definitely have a negative impact on Sri Lanka's population of Hog Deer. As there is some controversy to the exact status of the Hog Deer, some say that the species was introduced to Sri Lanka during the Dutch colonial period in the early part of the 1500s as a game animal, but taking into consideration the Hog Deer distribution in adjoining South Asian countries (Azam et al. 2002), it is highly unlikely that the Hog Deer was introduced to Sri Lanka during the stipulated period. However, to justify such a notion, genetic studies will have to be carried out on Hog Deer remains found in

Status of Hog Deer in Sri Lanka
Vishvanath et al.
ancient excavation sites, as well as living individuals to clarify the doubt. Compared to other species of deer found on the island the Hog Deer is found in highly populated areas, but goes unnoticed, since it sticks to forest patches and cinnamon plantations. During the harvesting season, as the cinnamon plots are cleared, these animals are displaced putting them into dire straits. The conservation of these animals is equally important for the future existence of the species. Well planned translocation porgrammes can be an effective method in conserving the species; such programmes have been initiated for the displaced animals in the Galle District by the Department of Wildlife Conservation. At the same time it is worth taking necessary steps to control and monitor the issues of licensed fire arms to plantation owners in doing so it could minimize the threat by manifold to the Hog Deer.
The clearing of forest reserves for the massive development project of the southern high way, which runs through the strong hold of the Hog Deer, has badly affected the animals, displacing it from its home range and pushing them to occupy isolated patches of forest and cinnamon plantations in adjoining areas. It is proposed that necessary steps be taken in building animal tunnels or corridors in suitable places to facilitate the movement of animals from one side to another. As clustering, isolated populations of Hog Deer could also have a negative impact on their gene pool by diluting it due to too much inbreeding.
In addition to these the foundation for the conservation of this small ungulate should be laid through proper environment education programmes aimed at school children and community groups.

Recommendations
-To carry out studies using camera traps, this would shed light on its population density, distribution and population structure.
-Carrying out of a long-term ecological study on Hog Deer in its current distributional limits covering population status, group structure and composition, food and feeding, so that consensus could be made in developing conservation action plans. -To carry out genetic studies on the population to determine its heterozygosity level to see whether the population is inbred. -To declare a protected area in the core area occupied by Hog Deer.