Temporal range: Miocene to present
|Adult female and offspring ( Muntiacus muntjak ), in Malaysia, September 2012|
|Genus:|| Muntiacus |
| Cervus muntjak |
Muntjacs ( /mʌntdʒæk/ MUNT-jak),  also known as the barking deer  or rib-faced deer,  are small deer of the genus Muntiacus native to South Asia and Southeast Asia. Muntjacs are thought to have begun appearing 15–35 million years ago, with remains found in Miocene deposits in France, Germany  and Poland.  Most are listed as least-concern species or Data Deficient by the International Union for Conservation of Nature (IUCN), although others such as the black muntjac, Bornean yellow muntjac, and giant muntjac are vulnerable, near threatened, and Critically Endangered, respectively.  
The present name is a borrowing of the Latinized form of the Dutch muntjak, which was borrowed from the Sundanese mēncēk. The Latin form first appeared as Cervus muntjac in Zimmerman in 1780.   An erroneous alternative name of Mastreani deer has its origins in a mischievous Wikipedia entry from 2011 and is incorrect. 
The present-day species are native to Asia and can be found in India, Sri Lanka, Myanmar, Vietnam, the Indonesian islands, Taiwan and Southern China. Their habitat includes areas of dense vegetation, rainforests, monsoon forests and they like to be close to a water source.  They are also found in the lower Himalayas (Terai regions of Nepal and Bhutan).
An invasive population of Reeves's muntjac exists in the United Kingdom and in some areas of Japan.  In the United Kingdom, wild deer descended from escapees from the Woburn Abbey estate around 1925.  Muntjac have expanded rapidly, and are present in most English counties and also in Wales, although they are less common in the north-west. The British Deer Society in 2007 found that muntjac deer had noticeably expanded their range in the UK since 2000.  Specimens appeared in Northern Ireland in 2009, and in the Republic of Ireland in 2010.
Inhabiting tropical regions, the deer have no seasonal rut, and mating can take place at any time of year; this behaviour is retained by populations introduced to temperate countries.
Males have short antlers, which can regrow, but they tend to fight for territory with their "tusks" (downward-pointing canine teeth). The presence of these "tusks" is otherwise unknown in native British wild deer and can be an identifying feature to differentiate a muntjac from an immature native deer. Water deer also have visible tusks  but they are much less widespread.[ citation needed ] Although these tusks resemble those of both water deer and the musk deer, the muntjac is not related to either of these (and they are not related to each other). The tusks are a quite different shape in each.
Muntjacs possess various scent glands that have crucial functions in communication and territorial marking. They use their facial glands primarily to mark the ground and occasionally other individuals, and the glands are opened during defecation and urination, as well as sometimes during social displays. While the frontal glands are typically opened involuntarily as a result of facial muscle contractions, the preorbital glands can be voluntarily opened much wider and even everted to push out the underlying glandular tissue. Even young fawns are capable of fully everting their preorbital glands. 
Muntjac are of great interest in evolutionary studies because of their dramatic chromosome variations and the recent discovery of several new species. The Indian muntjac (M. muntjak) is the mammal with the lowest recorded chromosome number: The male has a diploid number of 7, the female only 6 chromosomes. Reeves's muntjac (M. reevesi), in comparison, has a diploid number of 46 chromosomes. 
The genus Muntiacus has 12 recognized species:
A karyotype is the general appearance of the complete set of chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is discerned by determining the chromosome complement of an individual, including the number of chromosomes and any abnormalities.
The giant muntjac, sometimes referred to as the large-antlered muntjac, is a species of muntjac deer. It is the largest muntjac species and was discovered in 1994 in Vũ Quang, Hà Tĩnh Province of Vietnam and in central Laos. During inundation of the Nakai Reservoir in Khammouane Province of Laos for the Nam Theun 2 Multi-Purpose Project, 38 giant muntjac were captured, studied, and released into the adjacent Nakai-Nam Theun National Protected Area. Subsequent radio-tracking of a sample of these animals showed the relocation was successful. The species is also located in parts of eastern Cambodia, as well as the Annamite Mountains.
The leaf muntjac, leaf deer or Putao muntjac is a small species of muntjac. It was documented in 1997 by biologist Alan Rabinowitz during his field study in the isolated Nogmung Township in Myanmar. Rabinowitz discovered the species by examining the small carcass of a deer that he initially believed was the juvenile of another species; however, it proved to be the carcass of an adult female. He managed to obtain specimens, from which DNA analysis revealed a new cervid species. Local hunters knew of the species and called it the leaf deer because its body could be completely wrapped by a single large leaf. It is found in Myanmar and India.
The Southern red muntjac is a deer species native to Southeast Asia. It is formely known as the Indian muntjac or the common muntjac before the species was taxonomically revised to represent only populations of Sunda and perhaps Malaysia. The other populations being attributed to this species are now attributed to Muntiacus vaginalis. Muntjacs are also referred to as barking deer. It is listed as Least Concern on the IUCN Red List.
The water deer is a small deer species native to China and Korea. Its prominent tusks, similar to those of musk deer, have led to both subspecies being colloquially named vampire deer in English-speaking areas to which they have been imported. It was first described to the Western world by Robert Swinhoe in 1870.
Reeves's muntjac, also known as the Chinese muntjac, is a muntjac species found widely in southeastern China and Taiwan. It has also been introduced in the United Kingdom, Ireland, the Netherlands, Belgium, and Japan. It takes its name from John Reeves, a naturalist employed by the British East India Company in the 19th century.
The hairy-fronted muntjac or black muntjac is a type of deer currently found in Zhejiang, Anhui, Jiangxi and Fujian in southeastern China. It is considered to be endangered, possibly down to as few as 5–10,000 individuals spread over a wide area. Reports of hairy-fronted muntjacs from Burma result from considering the hairy-fronted muntjac and Gongshan muntjac as the same species. This suggestion is controversial. It is similar in size to the common muntjac.
The Gongshan muntjac is a species of muntjac living in the Gongshan mountains in northwestern Yunnan, southeast Tibet, Northeast India and northern Myanmar.
A single specimen of the Roosevelt's muntjac or Roosevelt's barking deer was presented to the Field Museum in 1929 following the Kelley-Roosevelts expedition organized by Theodore (Jnr) and Kermit Roosevelt. The specimen is slightly smaller than the common muntjac and DNA testing has shown it to be distinct from recently discovered muntjac species. It is a subspecies of Fea's muntjac, whose home range is mountains further northwest separated by lower land. However, without further evidence, the exact position of Roosevelt's muntjac cannot be stated. Berlin Zoo supposedly held this species between 1961 and 1972 but it could have been an Indian muntjac, subspecies annamensis.
The Cervinae or the Old World deer, are a subfamily of deer. Alternatively, they are known as the plesiometacarpal deer, due to their ankle structure being different from the telemetacarpal deer of the Capreolinae.
The Sumatran muntjac is a subspecies of Indian muntjac in the deer family which can be the size of a large dog. It was discovered in 1914, but had not been sighted since 1930 until one was snared and freed from a hunter's snare in Kerinci Seblat National Park, Sumatra, Indonesia in 2002. Two other Sumatran muntjac have since been photographed in the park. The Sumatran muntjac was placed on the IUCN Red List in 2008, but was listed as Data Deficient, as taxonomic issues are still unresolved. The distribution of the taxon is also uncertain and may be more extensive than suggested. It is possible that some previous sightings of the common muntjac in Western Sumatra were the Sumatran muntjac.
The 2000s witnessed an explosion of genome sequencing and mapping in evolutionarily diverse species. While full genome sequencing of mammals is rapidly progressing, the ability to assemble and align orthologous whole chromosomal regions from more than a few species is not yet possible. The intense focus on the building of comparative maps for domestic, laboratory and agricultural (cattle) animals has traditionally been used to understand the underlying basis of disease-related and healthy phenotypes.
The preorbital gland is a paired exocrine gland found in many species of hoofed animals, which is homologous to the lacrimal gland found in humans. These glands are trenchlike slits of dark blue to black, nearly bare skin extending from the medial canthus of each eye. They are lined by a combination of sebaceous and sudoriferous glands, and they produce secretions which contain pheromones and other semiochemical compounds. Ungulates frequently deposit these secretions on twigs and grass as a means of communication with other animals.
Phu Pha Thoep National Park, formerly known as Mukdahan National Park, is a national park in Mukdahan Province, Thailand. This park, one of the country's smallest national parks, is home to unusual rock formations and a cave with ancient hand paintings.
The Northern red muntjac is a species of muntjac. It is found in numerous countries of south-central and southeast Asia.
Clapgate Pits is a disused quarry near Broughton, Lincolnshire. This 1.0 ha site has been managed by Lincolnshire Wildlife Trust since 1996. It provides an environment for several plants which are rare in Lincolnshire: pale St John's-Wort, Squinancywort and Wall Germander. Until 1969 it was the most northerly site in Britain for Pasqueflower but these plants were apparently dug up by vandals.