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 ; tactile ; acoustic ; chemical
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
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
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:
Commensal/Parasitic Species:
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 )
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 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
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.
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
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:
Anti-predator Adaptations: cryptic
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 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); sexual ; 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)
