Blue duikers are most active at dawn and dusk (5) (10) (11) and feed mainly on fruit, as well as leaves, flowers, fungi, seeds and sometimes insects or even small animals (4) (5) (8). Like other duikers, they may follow feeding monkeys and birds through the forest, picking up the fruits that are dropped (2) (6). The blue duiker is monogamous, with pairs appearing to mate for life and living in a small territory, which is defended against other blue duikers and regularly scent-marked (2) (5) (6). Breeding occurs year-round (4) (10), with a single young being born after a gestation of between 196 and 216 days (5) (12). Young are able to run within half an hour of being born, though usually remain hidden in the undergrowth for the first few weeks of life (5) (6). Blue duikers become mature at around a year old, after which they are driven from the parental territory (6) (10), and are reported to live for up to ten years (2) (9).

The blue duiker is the smallest and one of the most abundant and widespread of all duiker species (4) (5). Like other duikers, this diminutive antelope has a distinctive stocky body, large hindquarters, arched back and short, slender legs, a body shape adapted for easy movement through dense undergrowth (4) (6) (7). The name “duiker” comes from an Afrikaans word meaning “diver”, these species being named for their habit of diving into cover when disturbed (6) (8); in the blue duiker this behaviour is often accompanied by a loud, sneezing whistle given by the male (2) (5). Coat colour is quite variable, depending on location (2) (4) (5), and ranges from slate grey to dark brown, with a bluish sheen on the back, which gives the blue duiker its common name (4) (9). The underparts are whitish (4), as is the underside of the tail, where slightly crinkled white hairs reflect light so well that on the dark forest floor the constantly flickering tail can resemble a light flashing on and off (2) (5). Blue duikers have large eyes, fairly small ears and a wide, flexible mouth adapted to feeding on fruit (2) (4). Sexes are similar in appearance (6) and both possess short, spiky horns, though these are sometimes absent in the female or hidden by a short crest of hair (4) (9) (10). Females may also be slightly larger than males (4) (10). All duikers have a good sense of smell (5) and possess large, obvious, slit-like scent glands in front of the eyes, used in scent-marking (4) (6) (10).

Widely distributed in central, eastern and southern Africa, from the Cross River in Nigeria to south-east Sudan and southwards to central Angola, and remnant forests and thickets in Zambia, Malawi, eastern Zimbabwe, and parts of central Mozambique. In South Africa, this species is mainly confined to the evergreen forest and thicket along the coast from northern KwaZulu-Natal to the eastern Western Cape province; there are no confirmed records from Swaziland and none from southern Mozambique, suggesting a break in distribution between their South African range and eastern Zimbabwe and central Mozambique. Also present on the islands of Pemba, Zanzibar and Mafia (East 1999; Wilson 2001; Hart and Kingdon in press).

Philantomba monticola, commonly known as the blue duiker, is found throughout Central and Southern Africa. Its range includes Nigeria to Gabon and Kenya to South Africa.

Biogeographic Regions: ethiopian (Native )

Blue duikers are widely but patchily distributed throughout central, eastern and southern Africa, from Nigeria east to Kenya and south to Angola, Zambia, Malawi, Zimbabwe and parts of central Mozambique, as well as on the islands of Zanzibar, Pemba and Mafia. They are also found in parts of South Africa, though there appears to be a break in the species' distribution between its South African range and populations in Zimbabwe and Mozambique (1) (2) (6).

Blue duikers are the smallest of the duiker species, weighing no more than 4 to 6 kg. They are typically 55 to 72 cm long, with a 7 to 12.5 cm tail that is black with a white underside. Coat color varies, depending on where the animal lives but the coat is typically brown, often with a blue tint. All males have a pair of grooved horns that are about 5 cm in height. Females may have horns as well, however, horns are frequently not present in females. Blue duikers are very similar in appearance to Maxwell's duikers (Philantomba maxwellii). However, the two can be distinguished by several key features, most notably blue duikers have a smaller skull, with a narrower nasal passage.

Range mass: 4 to 6 kg.

Range length: 55 to 72 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: ornamentation

Habitat and Ecology

Systems

• Terrestrial

Blue duikers can be found in a variety of forested areas, including rain forests, riverine forests, dense thickets, and montane forests. They are often found near human dwellings, and may use plantations as corridors in their habitat. Piles of dead trees or lumber are sometimes used as resting sites. However, the majority of their time is spent resting in the open or at the base of a tree; this allows them to keep their line of vision clear.

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: forest ; rainforest

Other Habitat Features: agricultural

The blue duiker inhabits a wide range of forest and wooded habitats, including lowland rainforest, gallery forest, coastal scrub farmland, dense thicket and montane forest up to elevations of 3,000 metres. It is found in both primary and secondary forest and can also survive in small patches of modified or degraded forest and thicket, including close to human settlements (1) (2) (4).

Blue duikers are frugivores and primarily feed on fallen ripe and unripe fruit, seeds, flowers, and fungi. They are ruminants, but have a relatively small rumen, which results in a rapid rate of food turnover. In association with rapid turnover, they prefer foods that are low in cellulose and starch with moderate fiber and protein content. They are, however, capable of digesting foods that are relatively high in tannins. Blue duikers spend up to 67 to 76% of their waking hours foraging for food within their territory.

Animal Foods: insects

Plant Foods: leaves; seeds, grains, and nuts; fruit; flowers

Other Foods: fungus

Primary Diet: herbivore (Frugivore , Granivore )

Blue duikers live in forested areas and feed primarily on fallen fruit. The fruit that they find on the forest floor is often dislodged by monkeys that inhabit the same areas. In addition to fruit, blue duikers feed on seeds, however, they apparently do not aid in seed dispersal, because they fully masticate their food. Blue duikers may play host to several parasites. Externally, they are often afflicted with ticks. Internal parasites include several species of Nematoda, Coccidia, Strongyles, Trichuridae, and Moniezia.

Mutualist Species:

• monkeys (Cercopithecidae)

Commensal/Parasitic Species:

• nematodes (Nematoda)
• coccidian parasites (Coccidia)
• blood worms (Strongyles)
• roundworms (Trichuridae)
• ruminant tapeworms (Moniezia)

The diminutive size of blue duikers leaves them vulnerable to many species, including but not limited to hyenas, wild dogs, African golden cats, leopards, crocodiles, baboons, python, civets, crowned eagles, monitors, and humans. They primarily use their visual and auditory senses in detecting predators. Once a predator is spotted, blue duikers will typically communicate alarm, which may include snorting, stamping, whistling, or flicking the tail, depending on the degree of danger. Once this message of danger has been received, a duiker's response is typically flight. Their long hind limbs make them excellent jumpers, able to quickly dive into dense vegetation and disappear. It is this ability that gave duikers their name, for the Afrikaans word meaning 'divers'.

Known Predators:

• hyenas (Hyena)
• wild dogs (Lycaon pictus)
• African golden cats (Profelis aurata)
• leopards (Panthera pardus)
• crocodiles (Crocodilia)
• baboons (Papio)
• python (Python)
• civets (Viverridae)
• crowned eagles (Harpyhaliaetus coronatus)
• monitors (Varanus)
• humans (Homo sapiens)

Anti-predator Adaptations: cryptic

Blue duikers use auditory, visual, olfactory, and tactile senses for communication. They have several methods of displaying alarm to a mate or offspring, including vocalizing and flicking the tail. Auditory signals include snorting, whistling, hitting an object with the horns, and stamping the feet. Each of these displays conveys different messages and may communicate alarm or sexual excitement. Their primary visual display is tail flicking; flicking the black tail reveals a white underside, which is believed to communicate imminent danger. Blue duikers have several scent glands, the most notable of which are the preorbital glands. Preorbital glands are thought to be important in communicating social acceptance and territory ownership. Pair members may scent mark each other, their offspring, or trees in their home range. Individuals often lick one another, a behavior that is thought to indicate social acceptance. Licking is especially evident when a male is courting a female.

Communication Channels: visual ; tactile ; acoustic ; chemical

Other Communication Modes: pheromones ; scent marks

Perception Channels: visual ; acoustic

In captivity, blue duikers typically live for 10 to 15 years, but the oldest recorded captive individual survived until it was nearly 16 years of age. In the wild, lifespan is shorter, with the oldest known individual surviving to age 12. Captive duikers are commonly afflicted with several illness, most notable of those is 'sloshing syndrome' or rumen hypomotility syndrome. This illness is characterized by a build-up within the rumen caused by limited activity.

Range lifespan

Status: wild: 12 (high) years.

Range lifespan

Status: captivity: 16 (high) years.

Typical lifespan

Status: captivity: 10 to 15 years.

Maximum longevity: 15.9 years (captivity) Observations: In the wild these animals live up to 12 years (Bernhard Grzimek 1990). One captive specimen was still alive after 15.9 years. A hybrid between a zebra duiker and a blue duiker lived 20.3 years (Richard Weigl 2005).

Blue duikers become sexually mature at 9 to 12 months for females and 12 to 18 months for males. Once sexually mature, they find a mate and remain paired for life. Although blue duikers are considered monogamous, males occasionally breed with other females.

Mating System: monogamous

Blue duikers are social animals and display a variety of social behaviors, but they do not form large groups, instead associating as mated pairs. An important aspect of behavior is their use of preorbital scent glands, which both genders use to mark their mate. Licking behavior is also displayed and is believed to indicate social acceptance.

Blue duiker pair members remain together throughout the year, spending much of their time in close proximity. Seasonality does not appear to influence their reproduction, as they continue to produce offspring without regard to time of year. After the female calves, the male leaves the territory for approximately one month, during which time other males may enter the territory. The return of the female's mate drives other males away.

Blue duikers have a gestation period lasting anywhere from 196 to 216 days and typically produce only one calf per reproductive event. Newborn calves weigh about 10% of the mother's body weight. After calving, the female conceals her offspring, and for the first several weeks after birth, the majority of contact between the calf and female takes place during nursing. Eventually, when the calf is more mature, it spends more time with its mother. The calf is weaned between 2.5 and 3 months of age, and eventually leaves the territory on its own accord. Female calves typically leave when they are sexually mature, which is between 1 and 1.5 years of age, and males when they are fully grown, at about 2 years of age. Usually, only one offspring associates with the parents at any one time, but occasionally a monogamous pair will share its territory with two offspring of different ages.

Breeding interval: Breeding interval is not reported, although mated pairs typically associated only with 1 or 2 offspring at a time until they mature at 1 to 2 years old, so breeding interval is likely to be once yearly.

Breeding season: Blue duikers breed throughout the year.

Range number of offspring: 1 to 2.

Average number of offspring: 1.

Range gestation period: 196 to 216 days.

Range birth mass: 710 to 954 g.

Average birth mass: 867 g.

Range weaning age: 10 to 12 weeks.

Range time to independence: 1 to 2 years.

Range age at sexual or reproductive maturity (female): 9 to 12 months.

Range age at sexual or reproductive maturity (male): 12 to 18 months.

Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous

Blue duiker calves are extremely precocial and are able to run within 20 minutes of birth. The mother typically allows the calf to nurse approximately 3 times a day for the first month, after which the mother reduces nursing events until the calf is weaned at 2.5 to 3 months. Initially, the male is absent, taking leave shortly after the calf is born, and returning approximately one month later. However, he does not travel far, and does occasionally come back and spend time with his mate. It is believed that the male leaves his territory to aid in the protection of his offspring.

Parental Investment: precocial ; female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female)

The following is a representative barcode sequence, the centroid of all available sequences for this species. 

 
There are 24 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
 

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 17
Species: 19
Species With Barcodes: 1

Currently, blue duikers are listed as 'Least Concern' on the IUCN Red List of Threatened Species.

CITES: appendix ii

IUCN Red List of Threatened Species: least concern

Classified as Least Concern (LC) on the IUCN Red List (1) and listed on Appendix II of CITES (3).

Population

Population Trend

Major Threats

The blue duiker is heavily hunted throughout its range and is one of the most important components of the bushmeat trade in many areas (1) (13) (14). Duiker species are particularly popular with hunters, as they are easy to catch, easy to transport and have enough meat to be highly profitable (15). However, the blue duiker appears able to withstand hunting pressure better than most of the larger duiker species and currently remains widespread and abundant (1) (2) (14). Other potential threats include habitat destruction through the felling of forests for fuel, building materials, agriculture and the spread of human settlement (10). The felling of fruit trees and killing of monkey species in particular may further degrade blue duiker habitat and food supply (2). Although the blue duiker is again better able to tolerate this threat than other duiker species, and indeed often survives in a range of human-modified habitats, the combination of hunting and habitat loss may threaten populations in some areas, leading to local declines (1)

Conservation Actions

This resilient species still occurs in large and generally stable numbers in most areas and is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning international trade in blue duikers should be carefully monitored and controlled (1) (3). The blue duiker should continue to survive in large numbers for the foreseeable future, provided human population densities remain low to moderate over large parts of its range. Although protected areas make up only a small part of its total range, its core populations are generally stable other than in areas where hunting pressures are particularly high (1).

Although this species sometimes occupies plantation fields, it is not known to be harmful to crops or humans.

Blue duikers are among the most common duikers hunted for bushmeat. Many human groups living near the Congo basin rely heavily on the meat obtained from duikers for food and income.

Positive Impacts: food