Muntiacus atherodes, commonly called Bornean yellow muntjacs, is found throughout the island of Borneo.
Biogeographic Regions: oriental (Native )
Other Geographic Terms: island endemic
Bornean yellow muntjacs are characterized by a yellowish-orange hue to their fur. They have a darker stripe on the nuchal region which becomes yellowish-orange on the sides and then whitish on the belly. The tail has a dark nuchal stripe and the pale ventral color and is 14 to 20 cm in length. The under part of the throat retains the ventral paleness. The ears are sparsely haired with coloration ranging from deep brown to yellowish or grayish brown with creamy or whitish markings (Nowak, 1999). Males have slender, simple horns of 16 to 42 mm in length. Males lack both frontal tufts of hair and antler burrs (Payne and Francis, 1985). Females have small, bony knobs and tufts of hair in place of horns. Males also have modified upper canines that curve strongly outward from the lips, forming small tusks (Norwak, 1999). At birth, fawns possess lines of white spots on the upper parts of their bodies. These spots remain until they are half their adult size (Payne and Francis, 1985).
Range mass: 13 to 18 kg.
Range length: 90 to 100 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: ornamentation
Bornean yellow muntjacs are terrestrial ungulates that live in variety of habitats, including moist forests, low hills, coastal regions, and areas of dense vegetation. They are not normally found far from water (Nowak, 1999). They are found from 0 to 1200m (ARCBC, 2006).
Range elevation: 0 to 1200 m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest ; rainforest ; scrub forest
Habitat and Ecology
Its diet includes herbs, seeds, grass and fruits (Payne et al. 1985). It is mostly active during the daytime (Payne et al. 1995, Yasuma and Abdullah 1997) but at least sometimes at night (Duckworth 1997). It lives in small territories and moves either in pairs or alone (Payne et al. 1995). Breeding seasonality is unknown.
Bornean yellow muntjacs feed on an assortment of vegetation: leaves, fruits, shoots, grasses, herbs, and seeds. They are mainly diurnal, feeding throughout the day.
Plant Foods: leaves; wood, bark, or stems; seeds, grains, and nuts; fruit
Primary Diet: herbivore (Folivore , Frugivore )
There is little available information on the ecosystem role of Bornean yellow muntjacs. They may help to disperse the seeds of fruit trees by eating them and they act as prey to large, forest predators.
Known predators of Bornean yellow muntjacs include clouded leopards (Neofelis nebulosa) and humans.
- clouded leopards (Neofelis nebulosa)
- humans (Homo sapiens)
Anti-predator Adaptations: cryptic
Life History and Behavior
Muntjacs, in general, are known as ‘barking deer’ due to the short, sharp, loud, and deep bark-like call they produce. When alarmed, the barking of Bornean yellow muntjacs can last for more than an hour. The frequency of barking increases in circumstances of reduced visibility (Nowak, 1999). A short, high-pitched mewing sound is emitted by females with young (Payne and Francis, 1985). Muntjacs also use the secretions from their pre-orbital glands to communicate reproductive state, territorial boundaries, and to cement social bonds.
Communication Channels: visual ; acoustic ; chemical
Perception Channels: visual ; tactile ; acoustic ; chemical
There is little available information on the lifespan of Bornean yellow muntjacs.
Little is known about mating in Bornean yellow muntjacs. Mating systems and behavior may be similar to other, better studied, species of muntjacs, where males compete for access to females in estrous.
Bornean yellow muntjacs are polyestrous and breed throughout the year. Their estrus cycle lasts between 14 and 21 days and gestation between 210 and 215 days. Typically a single fawn is born, very rarely twins. The fawn will stay hidden in thick vegetation until it is able to move about with its mother (Norwak, 1999). Weaning lasts between 2 months (Walker, 2006) to halfway into the next pregnancy, which will be conceived just a few days after a fawn is born (Whitehead, 1993). Sexual maturity will be reached within 6 to 12 months (Huffman, 2006).
Breeding interval: Female Bornean yellow muntjacs can have several offspring each year, depending on the availability of high quality nutrition.
Breeding season: Bornean yellow muntjacs breed throughout the year.
Range number of offspring: 1 to 2.
Average number of offspring: 1.
Range gestation period: 7 to 7.17 months.
Average weaning age: 2 months.
Range age at sexual or reproductive maturity (female): 6 to 12 months.
Range age at sexual or reproductive maturity (male): 6 to 12 months.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Females lactate and protect their young. Otherwise, little is known about parental investment in the young. Like other muntjacs, Bornean yellow muntjacs are somewhat precocial when born and develop rapidly.
Parental Investment: precocial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
Bornean yellow muntjacs are listed as primarily lower risk on the IUCN's 2006 Red List of Threatened Animals. Additionally, they fall into the sub-category of least concern (IUCN, 2006). However, hunting pressure on this species is high. They are attracted to grazing areas near roads and in forest cuts, making them more susceptible to hunting (Meijaard et al., 2006).
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
IUCN Red List Assessment
Red List Category
Red List Criteria
The extent to which habitat encroachment and hunting constitute threats specifically to M. atherodes is unclear, reflecting a paucity of studies to determine its resilience. Logging has been reported to lead to slight decreases in densities of the species, and this seems to be due to habitat change per se rather than elevated hunting (which usually accompanies logging; Bennett and Gumal 2001) because M. muntjak in the same study was found to increase strongly after logging (Heydon 1994). In the Sarawak Planted Forests, Bintulu Division, Sarawak, muntjacs (probably mostly this species) are among the commonest species camera-trapped in young Acacia mangium plantations (under four years old) and have been seen browsing on young acacia shoots. Footprints are common in the adjacent newly planted areas and forest fragments (Belden Giman pers. comm. 2008). However, this area contains a substantial proportion of natural, if somewhat degraded, forest, which in theory might be found to be necessary for populations in the highly altered habitats. Information on the species in landscape-scale plantations has not been traced. In terms of coping with fragmentation, M. atherodes has survived at least for several years in several forest isolates of 100 km² or less, Similajau National Park (Sarawak; J.W. Duckworth pers. comm. based on observations in 2005), Sepilok Forest Reserve (only 42 km²; muntjacs not confirmed as this species; Siew Te Wong pers. comm. 2008), and Sungai Wain (Kalimantan; G.M. Fredriksson pers. comm. 2008); in the latter, where there is little hunting except around the margins, it is common. But the current carving up of the formerly extensive forest of lowland Borneo is so recent that determining long-term persistence in such fragments is impossible; doomed populations in slow but fixed decline may account for records in fragmented and degraded areas. There is no good evidence that any muntjac is tied to old-growth forest, however, even in areas where two or more species are sympatric (R.J. Timmins pers. comm. 2008).
Muntjacs are widely and heavily hunted on Borneo for meat, skins, and as a source of traditional remedies (Bennett et al. 2000; Mohd Azlan J. pers. comm. 2008; Belden Giman pers. comm. 2008; G. M. Fredriksson pers. comm. 2008; A. C. Sebastian pers. comm. 2008; Siew Te Wong pers. comm. 2008). Traditionally, hunting used traps, dogs and spears, and blowpipes. Hunters in remote parts of the interior still use these methods, but most animals now die by gunfire. Sarawak held 60,000 legally registered shotguns while Sabah held almost 13,000 in the mid 1990s (Bennett et al. 2000). Methods used in Indonesia include guns and spotlights along logging roads, snaring, and dogs (G. M. Fredriksson pers. comm. 2008). The combination of dogs and guns may be particularly efficient (Belden Giman pers. comm. 2008). Snaring is still very heavy outside well-secured areas, but at least in some areas seems not to catch many of this species: Belden Giman (pers. comm. 2008) found during interviews with 75 longhouses inside the Sarawak Planted Forests (Bintulu) that the highest percentage (73% and 12%) of game species caught by snares were pigs and porcupines respectively; muntjacs (both species) totalled less than 2% of animals, even though in this area they are common. Shotguns remain the even bigger problem (Bennett et al. 2000; Mohd Azlan J. pers. comm. 2008; Siew Te Wong pers. comm. 2008). Unaccompanied packs of stray or even perhaps feral dogs are also likely to be a threat, particularly in forest isolates close to urban areas (e.g. Similajau National Park; J.W. Duckworth pers. comm. 2008). It is unlikely that hunters make any distinction between the two Bornean muntjac species directly, although it is plausible that M. atherodes is under higher hunting pressure than is M. muntjak reflecting its purported predominance in the lowlands, where most of the logging concessions currently lie. Plantation estates are also concentrated in the lowlands, but Bennett et al. (2000) found that hunting levels in them were low, not least because they supported so few animals would-be hunters had to journey to forest areas. Even when these were nearby, few labourers were hunting, because of the demands of their job, and, crucially, the disincentives by plantations companies for them to own shotguns. As non-locals with limited financial security, most followed employer rules preventing ownership of guns. Experience elsewhere shows that in such situations, local hunters may see such concentrations as potential markets, therefore leading to an increase in hunting even though it is not undertaken directly by the labourers. As plantations cover ever more Bornean lowlands, this may become a more significant stimulant of hunting. Also, although some ethnic groups, at least the Punan, have traditional beliefs against eating muntjac meat (Belden Giman pers. comm. 2008), over most of (at least) Malaysian Borneo, “in general, everyone will hunt and eat anything” (Bennett et al. 2000). Much hunting is for the market rather than local use, so there is a limitless demand. Bennett and Gumal (2001) profiled the hunting of ungulates in Sarawak in the mid 1990s thus: muntjacs (along with Bearded Pig Sus barbatus and Sambar Rusa unicolor) are heavily shot for wild meat trade across Sarawak, and these ungulates are the species most sought be the restaurants. Wild meat is widely sold in towns, villages, restaurants and logging camps throughout Sarawak; 250 sales outlets were estimated across the state in 1996, with an annual trade worth 3.75 million USD. Along the Rejang river alone, in the mid 1980s, 250 muntjacs were sold per year (Caldecott 1988). The market for meat is great and in the 1990s was probably expanding. There were, then, no controls on commercial hunting of non-protected species (including muntjacs). The implementation of the Master Plan for Wildlife in Sarawak (Wildlife Conservation Society and Sarawak Forest Department 1996) introduced a strict ban on all wildlife trade, shotgun ownership and cartridge sales in the late 1990s (Bennett and Gumal 2001). Substantial numbers of muntjacs are, nevertheless, still killed in the state, as they are elsewhere in Borneo.
Bennett et al. (2000) considered the effects of this onslaught upon muntjacs (not distinguished to species) through a lengthy hunting study in February 1993 to June 1995, in both Bornean states of Malaysia (Sarawak and Sabah), each with eight study areas. Muntjacs constituted only 4–11% of animals killed, but index counts of signs show an inverse relationship between sign index and hunting pressure so strong that the latter over-rode the effects of habitat variables in determining their densities. Hunting was so ubiquitous, even in protected areas, that in the two states, only one site (part of Danum Valley, Sabah) could be found as a control, where there was primary forest but negligible hunting levels. They concluded that “the only single factor offering any effective protection for [quarry species of] wildlife is difficulty of access”; whether animals are protected or non-protected species, inside or outside protected areas, had no significant restraint on hunting levels. Since that study, much forest has been converted and muntjac populations in the smaller and more isolated areas that remain must now be more vulnerable to local extinctions.
Heavy hunting with shotguns was found to be a severe problem for larger mammals and birds across Sarawak and the need for its control (of guns and of sale of ammunition, with firm legal underpinnings) was recognised in the Master Plan for Wildlife in Sarawak (Wildlife Conservation Society and Sarawak Forest Department 1996). As everywhere, people devise ways for circumventing the controls (illegal trade in bullets and locally made shot-guns, called bekakok, which have no administrative or legal paper-trail) and strong enforcement is required for the foreseeable future.
The long-term persistence of large populations of Bornean Yellow Muntjac, as distinct from isolated populations in well-secured protected areas, will depend upon their ability to use plantation landscapes of oil palm, rubber, acacia and others. Clarification of this is needed to assess the species’s conservation priorities. Of particular concern is the finding from Sabah suggesting that M. atherodes may be more a species of old-growth forest and M. muntjak the predominant species of logged areas (Heydon 1994). It is urgent to determine whether this is a generally applicable pattern across Borneo.
Close liaison with plantation estates and other employers of large numbers of labourers is essential as this offers the best medium to control hunting by employees. As the proportion of plantation rises this will become ever more important. Similar arrangements are needed with logging concession-holders, even more importantly because of the high hunting levels by loggers.
In future studies, ways of enhancing information specific to muntjac species need to be sought and implemented. Many of the studies reviewed here would not, for example, have detected wild changes in the relative proportions of the two muntjac species within their results concerning muntjac spp. This is a major concern, given that M. atherodes is everywhere sympatric with M. muntjak. With cheap digital cameras now available, some form of photography, by the hunter, of each animal killed should be considered (and this would be beneficial for other Bornean genera with closely similar species, e.g. chevrotains Tragulus). Most of the grey literature was not available to the present review and much could be learnt from a more comprehensive trawl of it and of active surveyors.
Relevance to Humans and Ecosystems
Bornean yellow muntjacs are considered a nuisance because they destroy trees by stripping off bark.
Negative Impacts: crop pest
Bornean yellow muntjacs are hunted for their skins and meat.
Positive Impacts: food ; body parts are source of valuable material
Bornean yellow muntjac
The Bornean yellow muntjac (Muntiacus atherodes) is restricted to the moist forests of Borneo where it lives alongside the common muntjac. It is similar to its much more common cousin and was only recently recognised as a separate species. Apart from the color difference, its antlers, which are just 7 cm (2.8 in) in length, are smaller than those of the common muntjac. It has not been extensively studied and has been described a relict species.
References[edit source | edit]
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