Blue duiker - WikiHQ

The blue duiker (Philantomba monticola) is a small antelope found in central, southern and eastern Africa. It is the smallest species of duiker. The species was first described by Swedish naturalist Carl Peter Thunberg in 1789. 12 subspecies are identified. The blue duiker reaches at the shoulder and weighs . Sexually dimorphic, the females are slightly larger than the males. The dark tail measures slightly above . It has short, spiky horns, around long and hidden in hair tufts. The subspecies show a great degree of variation in their colouration. The blue duiker bears a significant resemblance to Maxwell's duiker.

Activity is diurnal (limited to daytime). Secretive and cautious, the blue duiker confines itself to the forest fringes. Territorial, individuals of opposite sexes form pairs and occupy territories, nearly large and marked by preorbital gland secretions. The blue duiker feeds on fallen fruits, foliage, flowers and pieces of bark, provided mainly by the forest canopies in their habitat. The age when sexual maturity is gained has been given differently by different studies. The species is monogamous, with pairs remaining together throughout the year. The length of the gestational period has been estimated from as little as four months to as long as seven months. Births occur throughout the year, though the birth rate might fall in the dry season. The calf is mainly kept in hiding and weaning occurs at 2.5 to 3 months.

The habitat consists of a variety of forests, including old-growth, secondary, and gallery forests. Forests are preferred as these provide the animal with shelter through the dense understory and forage through the canopy. Though categorized as Least Concern by the International Union for Conservation of Nature and Natural Resources (IUCN), the blue duiker is under threat from extensive bushmeat hunting across its range.

Taxonomy and etymology

thumb|right|A blue duiker

The scientific name of the blue duiker is Philantomba monticola. It is placed in the genus Philantomba, along with Maxwell's duiker (P. maxwelli) and Walter's duiker (P. walteri), and the family Bovidae. The species was first described by Swedish naturalist Carl Peter Thunberg in 1789. It is sometimes treated as a species of Cephalophus, Owing to the remarkable similarities between the two species, some zoologists such as Theodor Haltenorth consider Maxwell's duiker as a race of the blue duiker.

While the generic name Philantomba has no clear origin, the specific name monticola has been derived from the Latin words montis (mountain) and colo (meaning "I cultivate" or "I inhabit"), in reference to its montane habitat. The common name "blue" refers to one of its typical coat colours. This cladogram, however, did not include the newly discovered Walter's duiker. Marc Colyn (of the University of Rennes 1) and colleagues, who had discovered this species in 2010, had prepared a similar cladogram (below) that included it.

Subspecies

As many as 16 subspecies of the blue duiker have been proposed. In 1997, Jonathan Kingdon demarcated seven major populations of the species.

The grey-legged or northern subspecies

thumb|Blue duiker skeleon ([[Museum of Osteology)]]P. m. aequatorialis (Matschie, 1892) – The range, bounded by the Congo River on the west, extends from the Democratic Republic of Congo into Uganda, and up to the Nile River. It is also found to the northeast of the Imatong Mountains (South Sudan).
P. m. congicus (Lönnberg, 1908) – The range extends from the east of the Cross River across the Ubangi River to the Congo River, till Lisala (Democratic Republic of Congo). It is also found north of the mouth of the Congo River and in Cameroon and Gabon.
P. m. lugens (Thomas, 1898) – The range extends from the Southern Highlands of Tanzania till the Malawi border, though it may occur in the Nyika Plateau in northern Malawi.
P. m. melanorheus (Gray, 1846) – The type locality is Bioko, Equatorial Guinea.
P. m. musculoides (Heller, 1913) – Occurs in eastern Ugandan and Kenyan forests. The range extends as far east as the East African Rift.
P. m. sundevalli (Fitzinger, 1869) – It occurs in the eastern African coast, and on the islands of Mafia, Pemba and Zanzibar.

The red-legged or southern subspecies

P. m. anchietae (Bocage, 1879) – The type locality is northern Angola.
P. m. bicolor (Gray, 1863) – The range extends from Zanzibar to the KwaZulu Natal region in South Africa.
P. m. defriesi (W. Rothschild, 1904) – The type locality is to the west of the steep cliffs in the Muchinga Province (Zambia).
P. m. hecki (Matschie, 1897) – Occurs in Malawi, east of the valley of the Luangwa River (Zambia) and northern Mozambique.
P. m. monticola (Thunberg, 1789) – Occurs in the Eastern Cape and Western Cape provinces of South Africa.
P. m. simpsoni (Thomas, 1910) – Occurs between the lower Congo River and its tributary Kasai River.

Description

thumb|left|A close view of a blue duiker

The blue duiker is a small antelope; in fact, it is the smallest duiker. The head-and-body length is typically between . It reaches at the shoulder and weighs nearly . P. m. anchietae is the largest subspecies. The pedal glands (near the hooves) produce a pungent, whitish fluid. Walter's duiker is notably lighter in colour; the flanks are brown instead of grey. A vocal bovid, bird-like chirps denote curiosity in the animal. It can let out yowls typical of cats if distressed. A female not in oestrus will avoid the male's advances, and may even let out a whistling call. may also be included in the diet. The blue duiker can sustain itself on dead foliage better than other duiker species. In 2001, American zoologist Don E. Wilson observed 18 stomachs, and concluded that nearly three-fourths were occupied by fruits, browse took 15 percent of the volume, while fungi and flowers took 5 percent each. to as long as seven months. The former estimate is supported by observations in the Ituri Rainforest (Democratic Republic of Congo). Births occur throughout the year, though the birth rate might fall in the dry season. A postpartum oestrus occurs three to five days after the birth.

Threats and conservation

The blue duiker is categorized as Least Concern by the International Union for Conservation of Nature and Natural Resources (IUCN). It is listed in Appendix II of the Convention on International Trade in Endangered Species (CITES). While the population trend is reasonably stable, the blue duiker is threatened by extensive bushmeat hunting across its range. Wilson claimed that the blue duiker has the greatest economic as well as ecological significance of any African ungulate.