Axis kuhlii [Müller, 1840].

Citation: In Temminck, Verh. Nat. Gesch. Nederland. Bezitt., Zool., Zoogd. Indisch. Archipel., p. 45[1840].

Type locality: "Java en Borneo", but is found only on Bawean Island, Indonesia.

The taxonomic record (above) is taken from Wilson and Reeder (1993). Axis kuhlii is included in the subgenus Hyelaphus [Sundevall, 1846] along with the closely related hog deer (A. porcinus) and Calamian deer (Axis calamianensis) (Whitehead, 1993). It is considered by some authors to be a subspecies of A. porcinus (see Wilson and Reeder, 1993). A. kuhlii is a monotypic species (Whitehead, 1993), and there are no synonyms.

The Bawean deer is poorly studied, and few scientific measurements of this species are available. There is no consensus about either adult weight or total length, although reported values of 50-60 kg and 140 cm seem more likely than those provided by Kurt (1990) as they refer directly to A. kuhlii. Shoulder height is 65-70 cm.

The coat is short, smooth, and soft; the color is generally a light teakish-brown (Sitwell, 1970). Although the pelage is a relatively uniform in color from a distance, each hair is banded with yellow which gives the coat a more grizzled appearance up close (Sitwell, 1970). The few distinctive markings are limited to the head and neck, where there is a light throat patch or 'bib' and usually a whitish eye-ring (Blouch and Atmosoedirdjo, 1987; Geist, 1998). The light lip area is separated from the face by a darker band. The moderately long tail is bushy, being brown above and white on the underside (Lydekker, 1915; Sitwell, 1970; Whitehead, 1993). White hairs are also present around the groin (Sitwell, 1970).

The size and shape of the Bawean deer are virtually identical to the hog deer (A. porcinus), although the legs of A. kuhlii are noticeably shorter (Geist, 1998). Like many other inhabitants of dense forest, the body is lower at shoulder than at the hip and thus Bawean deer look like they are constantly crouching (Blouch and Atmosoedirdjo, 1987). The face is short compared to that of the hog deer (Lydekker, 1915; Whitehead, 1993). The inflated tympanic bullae of the skull are found only among Hyelaphid deer (A. kuhlii, A. porcinus, and A. calamianensis) (Geist, 1998). The ears are small and pointed and are densely haired on their exterior surface (Lydekker, 1915).

Only the males bear the slender three-tined antlers (Sitwell, 1970). Similar in form to those of the hog deer, the antlers have a brow tine (found just above the base) and a forked main beam (Blouch and Atmosoedirdjo, 1987). However the antlers of A. kuhlii are much shorter than those of A. porcinus, generally not growing longer than head (Lydekker, 1915; Whitehead, 1993). The longest main beam recorded by Blouch and Atmosoedirdjo (1987) was 47 cm in length, while the leading trophy in Rowland Ward's Record of Big Game has a length of only 24.8 cm, with a 7.3 cm basal circumference, and a 27.6 cm inside span (Whitehead, 1993). The antlers are supported by relatively long pedicels, permanent outgrowths of bone from the forehead (Whitehead, 1993). Bucks may be found with hard antlers at all times of the year (Blouch and Atmosoedirdjo, 1987).

Whitehead (1993) reports a seasonal rut in September and October, although males may be found in breeding condition (i.e., with hard antlers) throughout the year (Blouch and Atmosoedirdjo, 1987). The gestation period is 225-230 days, after which a single fawn is born - cases of twins are known but very rare (Blouch and Atmosoedirdjo, 1987; Whitehead, 1993). The majority of births occur from February to June, although occasional births may occur in other months (Blouch and Atmosoedirdjo, 1987). In captivity, breeding may occur year-round, with females maintaining an interbirth interval of 9 months (Blouch and Atmosoedirdjo, 1978). However, in the wild it is unlikely that a female could raise more than one fawn per year (Blouch and Atmosoedirdjo, 1987).

Geist (1998) reported that fawns are only faintly and sparsely spotted and lose their spots very quickly, while Sitwell (1970) observed a fawn on Bawean at least three months of age with a row of white spots along either side of the spine. Males begin to grow antlers at about one year of age (Sitwell, 1970).

A. kuhlii is an inhabitant of upland forests, rather than low-lying marshy grasslands preferred by the closely-related hog deer (Geist, 1998). Forests with dense undergrowth are used for shelter, providing a refuge in which the deer sleep and rest during the day (Blouch and Atmosoedirdjo, 1978). The optimal cover appears to be brushy growth of woody plants no more than 3 meters high (Blouch and Atmosoedirdjo, 1987). In areas disturbed by humans, Bawean deer spend the day in forests on steep slopes that are inaccessible to teak loggers; clearings (rarely over 5 hectares in size) predominated by grasses such as lalang (Imperata cylindrica) are used extensively by Bawean deer at night. This is especially true during the first months after a fire, when the new vegetation is fed upon heavily (Blouch and Atmosoedirdjo, 1978). Individuals are occasionally sighted on the beach in the southwestern part of the island; otherwise they are rarely seen (Blouch and Atmosoedirdjo, 1987)

Secondary forest appears to be ideal Bawean deer habitat, supporting densities of 19.2 deer per square kilometer. Such habitat is characterized by tree species such as Ficus variegata, Macarange tanarius, and Anthrocephalus indicus which form an overstory under which shrubs such as Leea indica, Ficus sp., Antidesma montanus, and Garcinia celebica grow. Primary forests, teak (Tectona grandis) forests with understory, and areas with teak and lalang support densities of 3.3 to 7.4 deer per square kilometer, while other habitats - such as regions dominated by Melastoma polyanthum and Eurya nitida brush, Rombok (Merremia peltata), disturbed primary forest, and teak without understory - support only 0.9-2.2 deer per square kilometer (Blouch and Atmosoedirdjo, 1987).

The Bawean deer has no natural predators except large reticulated pythons (Python reticulatus - a python was found by Blouch and Atmosoedirdjo (1978) with an adult deer in its stomach). However, pythons are not common and likely have little impact on the deer population (Blouch and Atmosoedirdjo, 1987). It is possible that wild pigs and macaques sometimes kill young fawns, although no evidence has been found to support this (Blouch and Atmosoedirdjo, 1978; Blouch and Atmosoedirdjo, 1987). Feral dogs are currently the greatest cause of mortality to this species, being responsible for 9 out of the 11 deaths examined by Blouch and Atmosoedirdjo (1987) between October 1977 and May 1979.

Blouch and Atmosoedirdjo (1987) observed Bawean deer feeding on 39 plant species, the bulk of which are forbs (15 species) and grasses (14 species). Young lalang grass (Imperata cylindrica) is a major food source for A. kuhlii, both because of its abundance and its apparent palatability to this species, although mature (old) lalang is never eaten. The grasses Paspalum conjugatum and Axonopus compressus also appear to be preferred, and although these species are rarer than lalang they are eaten in all stages of growth. Of the forbs, Lygodium circinnatum, Musa spp., Tridax procumbens, Pericampus glaucus, and Euphorbia geniculata are commonly fed upon. Browsing was observed on eight species of woody plants, but was primarily confined to young leaves and twigs of Ficus and rombok (Merremia peltata). These food sources are generally available throughout the year on Bawean, and are so abundant that conspicuous signs of feeding are rarely found. When in season, the fruits of Irvingia malayana and Elaeocarpus glaber are eaten in large quantities. Bawean deer frequently enter agricultural fields at the edge of forest at night, feeding on the young leaves of corn and cassava, but also on grasses and forbs growing among the crops (Blouch and Atmosoedirdjo, 1987). Each deer deposits approximately 13 fecal pellet groups per day, a number which has been used to estimate population numbers (Blouch and Atmosoedirdjo, 1978).

Blouch and Atmosoedirdjo (1978, 1987) have conducted the most behavioral research on this species. Except where noted, the information presented here is from these two papers.

The Bawean deer is primarily nocturnal, emerging from dense cover just after dark (around 1800 hours) and being active intermittently throughout the night. Peaks of activity occur approximately every two hours, usually separated by retreats into cover. As the night progresses, foraging periods become shorter and rests become longer, until the animals retire back into dense cover at sunrise. An individual deer may return to the same general hiding place for several days.

A. kuhlii is usually solitary, although pairs made up of a doe and fawn or a buck following a doe are also encountered. During nightly foraging in open clearings, Bawean deer may encounter other conspecifics, although Blouch and Atmosoedirdjo (1978) state that this cannot be considered a true "congregation". These open clearings, while used extensively for feeding, are also the center of social activity, with courting, challenging, fighting, and mating all occurring outside of the dense forest. Trails made by deer are commonly found leading from forest sites to feeding areas in brushy teak and secondary growth at lower elevations.

A. kuhlii communicates extensively with vocalizations, primarily using short, sharp barks. Both sexes create these sounds, although the calls of does are slightly higher pitched than barks made by males. Commonly, one call consists of five to ten barks strung together, audible to humans up to 100 meters away. If a pair of deer are surprised and separated, one or both will bark one to three time after a few minutes in an attempt to reestablish contact. If a mother is separated from her fawn, the doe will call, to which the youngster responds with a high pitched squeak audible only at a short distance.

The most sustained barks are performed by males as a challenge to rivals - one male was observed barking 95 times within a fifteen-minute period. This challenge-barking is often accompanied by foot stamping, audible to humans 40 to 50 meters away, and by snorts. Other bucks will approach a deer giving this call and answer it with a similar bark. Such challenges may escalate into a fight among males in which the antlers are used, especially if a receptive female is in the vicinity. Because the deer respond to and approach vocalizing conspecifics, humans can incite individuals to approach by imitating this call with a whistle.

Although highly vocal amongst themselves, Bawean deer do not appear to have an alarm call. When mildly alarmed, Bawean deer do not vocalize, but rather sneak quietly into cover in an attempt to escape undetected. Likewise, if approached in hiding, individuals frequently remain still in an attempt to remain unnoticed, or move quietly away from the potential threat. If startled, Bawean deer will sprint for a short distance and then move on quietly. The body form, with low shoulders and a higher rump, is conducive to moving through dense undergrowth, which these deer do with a crouching gait (Sitwell, 1970). They are very wary, and appear to avoid contact with humans, although with protection this appears to be changing.

Other forms of communication are poorly studied. Bucks will rub their antlers against small saplings, shredding off the bark, which Blouch and Atmosoedirdjo (1987) suggest may serve as visual communication. Captive deer regularly rub objects with their preorbital glands (likely with scent marking functions).

A. kuhlii is endemic to Bawean, a 200-220 km² island located in the Javan Sea between the islands of Java and Borneo (Blouch and Atmosoedirdjo, 1978; Geist, 1998). Two wild populations exist on the island, one found among the island's central mountain range, and other based around Mount Bulu in the southwestern quadrant of the island. A peninsula on the north-west side of the island (Tanjung Cina) has been heavily used by this species in recent decades (Semiadi et al., 2008). Restricted to this tiny island, A. kuhlii has the most restricted range of any extant deer species (Blouch and Atmosoedirdjo, 1987).

Countries: Indonesia (IUCN, 2002).

The Bawean deer is classified as critically endangered (Criteria C2a(ii)) by the IUCN (2009) and is on CITES Appendix I (CITES, 2006). The wild population is estimated at about 250 individuals (Semiadi et al., 2008), down slightly from the estimate of 300 by Blouch and Atmosoedirdjo (1987). Most of the wild population is found in a single subpopulation (Semiadi et al., 2008). Major threats to this species include habitat loss, with secondary forest habitat being converted to teak plantations and agricultural areas, and predation by feral dogs (Blouch and Atmosoedirdjo, 1978). The invasive plant Eupatorium odoratum may also reduce habitat quality (Semiadi et al., 2008). Hunting by humans, while previously a pressure on the population for hundreds of years, stopped in 1977 (Blouch and Atmosoedirdjo, 1987).

Axis (Latin) is said to be Pliny's name for the chital (Axis axis), although some records show it as "an unknown wild animal in India". Dr. H. Kuhl (1796-1821) was a German naturalist who was in the East Indies in 1820 and 1821.

Some confusion has resulted from this species' type locality: "Java en Borneo" - no known native populations of this deer are known off of Bawean island (Wilson and Reeder, 1993). According to Sitwell (1970), this species was first "discovered" by Salomon Müller in 1836, based on observations of a small herd kept in a local governor's private in the town of Tuban on the northern coast of Java. Only after the formal description was made was the true range of this diminutive deer revealed.

The Bawean deer may have been derived from a Pleistocene Javan Axis species (Axis oppenoorthi or A. lydekkeri) at a time when Bawean was connected to Java via a land bridge (Blouch and Atmosoedirdjo, 1987; Geist, 1998). It has also been suggested that this deer was introduced to the island by early European settlers, although this seems doubtful (Sitwell, 1970), especially on the basis of fossil evidence (see Semiadi et al., 2008).

Local names

Menjangan Bawean [Bahasa Java] (Whitehead, 1993)

Rusa bawean [Indonesia] (Whitehead, 1993)

Uncal Bawean [Bahasa Sunda] (Whitehead, 1993)

 

French

Cerf-conchon de l'ile Bawean, Cerf de Bawean (Kurt, 1990; Whitehead, 1993)

 

German

Kuhhirsch, Bawean-Schweinshirsch, Bawean Hirsch (Kurt, 1990; Whitehead, 1993)

 

Spanish

Ciervo de Kuhl, Ciervo porquerizo de Kuhl (IUCN, 2002)