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Philantomba maxwelliiMaxwell's duiker

By Justin Skrzynski

Geographic Range

Philantomba maxwellii inhabits an area of western Africa extending from Senegal and Gambia to Nigeria. Members of the species generally prefer lowland rainforests, second growth forests and forests relics found in savannas. ("Cephalophus maxwelli", 1982; Happold, 1987; Ralls, 1973)

Habitat

Maxwell’s duikers inhabit rainforest areas, relic forests in savannas, secondary growth forests and clearings in rainforests. Individual P. maxwellii are able to live in a wide variety of habitats because of their wide and adaptable food habits, which allow them to find adequate supplies of food in both primary and secondary forests as well as cleared areas. (Happold, 1987; Hofmann and Roth, 2000)

Philantomba maxwellii individuals prefer dense foliage where they can remain concealed. Maxwell’s duikers rarely stray more than 30 m from cover. Individuals make trails through the underbrush in their respective territories. (Coe, 1975; Ralls, 1973)

Physical Description

Maxwell’s duikers are small antelopes, averaging about 66 cm in length and 5 to 7 kg in weight. They have short legs and an arched back and stand 35 to 38 cm tall. Females are reported to be larger in length and mass than males. (Happold, 1987; Ralls, 1973)

The pelage of P. maxwellii is grey or grey-brown and paler on the animal’s underside. Maxwell’s duikers are more uniform in color than closely related blue duikers, Philantomba monticola, which are more sharply bicolored and bear areas of white fur on their buttocks. Maxwell’s duikers have short, bushy tails with a fringe of white fur around the edges. Two white stripes run symmetrically down an animal's head from its horns above its eyes, to its nose. Conspicuous suborbital glands are present below each eye. (Happold, 1987; Ralls, 1973)

Maxwell’s duikers have small, pointed horns that extend backwards from the rear of the skull. Horns are present in both sexes and emerge in the male when it is about two and a half months old. The animals also have a small tuft of dark hair on the tops of their heads. (Happold, 1987; Kingdon, 1974; Ralls, 1973)

Philantomba maxwellii has pedal glands in its feet, which consist of a small sac in the interior of the foot that leads to the exterior via a narrow canal. This trait is useful in differentiating P. maxwellii from the related blue duiker, whose pedal glands lack the long canal. (Happold, 1987; Ralls, 1973)

  • Range mass
    5 to 7 kg
    11.01 to 15.42 lb
  • Average length
    36-40 cm
    in

Reproduction

A male duiker forms bonds and mates exclusively with one female, even when a surplus of females is present. (Kingdon, 1974)

Male duikers smell or lick the urine of females and demonstrate flehmen, which is a behavior in which the animal retracts its upper lip and opens its mouth. This behavior is considered to somehow aid the animal in sensing pheromones and ascertaining the sexual status of females. (Ralls, 1973)

Male Maxwell’s duikers engage in a simple courtship wherein the male chases and bites the female. After a period of chasing, the male and female circle one another, after which the male approaches the female from behind, kicking its foreleg between the hindlegs of the female. Copulation ensues shortly thereafter. (Ralls, 1973)

Female P. maxwellii breed about once a year and give birth to a single young. Duikers time their mating so that young are born in the dry season (January to March) or the “little dry season” (August to September). (Kingdon, 1974)

The gestation period is about 120 days. Labor for this species lasts 20 to 30 minutes. After the infant duiker is born, the mother cleans it thoroughly with its tongue and eats any membranous material clinging to it. Newborns are capable of standing and walking within hours of birth, and one was reported as being able to run within 25 minutes of birth. Newborn Maxwell's duikers are "hiders" and generally remained concealed. A young duiker gains about 50 g per day by drinking its mother’s milk. Female duikers nursing their young must drink ample quantities of water. After about 2 weeks, young Maxwell’s duikers are able to begin foraging on their own. Weaning follows soon afterwards, although young duiker continue to nurse occasionally until 2 months of age. Full maturity is reached in about three years. (Happold, 1987; Kingdon, 1974; Ralls, 1973)

  • Breeding interval
    Maxwell's duikers breed about once a year.
  • Range number of offspring
    1 to 1
  • Range gestation period
    4 (low) months
  • Average gestation period
    4 months
  • Average weaning age
    0.47 months
  • Average age at sexual or reproductive maturity (female)
    3 years
  • Average age at sexual or reproductive maturity (male)
    3 years

Maxwell’s duikers provide little in terms of parental care. Young duikers usually spend their time in concealed areas and seek out their mothers only for nursing; female duikers were not witnessed to seek out their offspring even to nurse them. Maxwell’s duikers nurse with mother and young antiparallel to one another. Soon after a young Maxwell's duiker begins foraging on its own, at about 2 weeks of age, its mother begins to discourage it from nursing. Female duikers lick their infants as a method of grooming them. (Ralls, 1973)

Lifespan/Longevity

Little information is known of the lifespan of P. maxwellii in the wild, but they are known to live as long as 10 years in captivity. (Kingdon, 1974; Ralls, 1973)

  • Range lifespan
    Status: captivity
    10 (high) years

Behavior

Philantomba maxwellii is primarily nocturnal, in some instances it may be active in the early morning, late afternoon, and evening. Philantomba maxwellii moves with jerky motions and flicks its tail rapidly up and down. Animals of this species rarely stray more than about 20 or 30 m from the dense foliage they use for cover. (Happold, 1987; Ralls, 1973)

Maxwell’s duikers primarily form monogamous pairs or live alone. However, in areas in which territories overlap or in captivity, duikers interact socially. Individuals may rub heads in such a way as to transfer secretions from their suborbital glands onto one another. This is most common in male-female interactions, less so in female-female interactions, and rare in male-male interactions. Mutual grooming also occurs in social situations. (Happold, 1987; Kingdon, 1974)

Introduction of a foreign duiker into an established group usually leads to increased head-rubbing among group members and increased territorial marking by both males and females. As a rule, duikers also generally increase marking when a new duiker of the same sex enters their territory. Males are known to fight with foreign duikers. Male Maxwell’s duikers charge at each other, colliding heads and pressing their faces together, alternately pressing their left and right suborbital glands against one another. These fights end with one duiker fleeing, pursued by the other. Fleeing duikers are known to make jumps of almost 2 m in height and often collide with objects in their flight. (Happold, 1987; Kingdon, 1974; Ralls, 1973)

Home Range

Maxwell’s duikers have set areas in which they create pathways through the vegetation. Males mark their territorial perimeter before feeding and resting. This is accomplished with the suborbital gland, the secretions of which the animal rubs onto noticeable objects. Duikers mark their territories frequently, which, in areas where their territories overlap, communicates social information. Duikers set aside different areas within their territories for defecation, urination, and sleeping. (Happold, 1987; Kingdon, 1974)

Communication and Perception

Of primary importance in communications among Maxwell’s duikers is the use of the suborbital gland in marking both territories and other duikers. Male duikers frequently mark their territories, when most active marking an average of 5.6 objects every ten minutes. Females mark about 2.8 objects every ten minutes. Maxwell’s duikers frequently rub heads, rubbing suborbital secretions on one another. Territorial marking and head rubbing increase when a foreign duiker is introduced into an established group. This indicates that such marking serves not only as a means of advertising territory, but also of reinforcing social relationships. Interestingly, while the behavior of Maxwell’s duikers in using the suborbital gland is well documented, little is reported concerning how Maxwell’s duikers react to these chemical markers. (Happold, 1987; Ralls, 1973)

In addition to suborbital secretions, Maxwell’s duikers smell or taste one another’s urine. When a male samples a female’s urine, he exhibits flehmen behavior, which is characterized by a curled upper lip and open mouth. It is hypothesized that flehmen is somehow useful in helping the animal detect pheromones in the urine. Females also sample male urine, but with less frequency. (Ralls, 1973)

Maxwell’s duikers make an “alarm whistle,” though it is not reported in what context these whistles are used or how other duikers react to them. (Ralls, 1973)

Food Habits

Maxwell’s duikers are herbivores and mainly feed on the leaves of small forest plants such as herbs and shrubs. They rarely graze on grasses and are classified as browsers. They feed heavily on the leaves of Thonningia sanguinea, Canthium vulgare, and Alchornea cordifolia. (Happold, 1987; Hofmann and Roth, 2000)

Maxwell’s duikers also eat fruit, which varies seasonally in abundance. Over the seasons, a total of 78 different types of fruit were eaten with an average of about 3 different species of fruit being consumed by an individual duiker at any one time. Preference varies seasonally; for example, during January and February, duikers prefer Phoenix reclinata, Griffonia simplicifolia, Nauclea latifolia, Ficus capensis, Alchornea cordifolia and Blighia sapida. (Hofmann and Roth, 2000)

Other foods consumed by P. maxwellii are blossoms, roots, tubers, and fungi, although these foods constitute only a very small portion of the animals’ diets. Although it is speculated that ants are a natural part of the diets of many species of duikers, they have so far been found only in the stomachs of several Maxwell’s duikers. The ant species consumed were Paltothyreus tarsatus and Oecophylla longinoda. Some duikers in captivity have been seen to eat young birds, although this behavior has not been observed in the wild. (Hofmann and Roth, 2000)

Maxwell’s duikers prefer leaves to fruit only during the dry season when tubers and flowers are also present. They show no seasonal variation in the number of species of fruit that they eat. (Hofmann and Roth, 2000)

  • Animal Foods
  • birds
  • insects
  • Plant Foods
  • leaves
  • roots and tubers
  • fruit
  • flowers
  • Other Foods
  • fungus

Predation

Maxwell’s duikers are small, nocturnal, and skittish, making them difficult to observe in the wild. Humans avidly hunt this species but duikers have several natural predators as well. These predators include crowned eagles (Harpyhaliaetus coronatus) and leopards (Panthera pardus), as well as local species of pythons and other wild cats. (Happold, 1987; Ralls, 1973)

Maxwell’s duikers issue an “alarm whistle,” but can also make a bleating noise when in danger, such as when confronted and cornered by another duiker or handled by a human. When Maxwell’s duikers are nervous or threatened, they freeze as they are, sometimes in mid-stride. (Ralls, 1973)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Maxwell’s duikers most likely aid in the distribution of the seeds of the plants whose fruit they eat. More seeds are destroyed during digestion than are effectively disseminated in the their feces. Small seeds, however, may be effectively dispersed, and seeds of plants in the families Solanaceae and Cecropiaceae are distributed in this manner. Plants of the genus Ficus, whose fruits have small seeds and are heavily consumed by duiker are most likely dispersed this way. Some duiker spit out seeds during rumination. (Hofmann and Roth, 2000)

Duikers are known to interact with baboons (Papio) in areas where the two species overlap. Maxwell’s duikers follow monkeys and eat fruit that the monkeys dislodge from the trees. (Kingdon, 1974; Ralls, 1973)

Several parasites are known to use P. maxwellii as a host. These include the blood parasite Theileria mutans, the nematodes Thrichuris ovis and Setaria labiata-papillosa, the cestode Avitellina centripunctata, and 8 types of tick. Maxwell’s duiker serve as food for the predators listed above. (Ralls, 1973)

  • Ecosystem Impact
  • disperses seeds
Mutualist Species
  • Plants of the genus Ficus
  • Plants of the family Solanaceae
  • Plants of the family Cecropiaceae
Commensal/Parasitic Species
  • The blood parasite Theileria mutans
  • The nematodes Trichuris ovis and Setaria labiata-papillosa
  • The cestode Avitellina centripunctata
  • At least 8 species of ticks

Economic Importance for Humans: Positive

Maxwell’s duikers are hunted by local peoples for their skins. The Mano and Gio peoples of the Mount Nimba Range in Liberia use large deadfall traps to catch these duikers. These traps can kill the animals, but duikers are also taken alive and are available for sale. In addition to being hunted and trapped for their skins, they are hunted for meat, which is available in large bushmeat markets and can provide hunters with a large and sustainable income. Maxwell’s duikers are rarely hunted for trophies due to their small size. Methods for trapping Maxwell’s duikers outside the Mount Nimba area include firearms and nets and snares placed on frequently used duiker trails. (Coe, 1975; Hofmann and Roth, 2000; Ralls, 1973)

  • Positive Impacts
  • food
  • body parts are source of valuable material

Economic Importance for Humans: Negative

There are no known adverse effects of P. maxwellii on humans.

Conservation Status

Duiker populations have decreased from excessive hunting and habitat destruction. Of prime importance in the decreasing populations is the increased use of firearms by native populations in hunting these animals. While Maxwell’s duikers are not endangered, it is certain that their populations are below previous maximum levels. However, it is thought that the species will remain in abundance as long as ample habitat is available. ("Cephalophus maxwellii", 2004; Coe, 1975; Happold, 1987; Ralls, 1973)

Other Comments

Maxwell's duikers were considered by some to be the same species as blue duikers, but are argued by others to be different species based on pelage color, the morphology of the pedal gland in the foot, which has a deeper canal in P. maxwellii, and the smaller skull size of P. monticola. ("Cephalophus maxwelli", 1982; Kingdon, 1974; Ralls, 1973)

The word duiker was first used by Dutch settlers in Africa and means “diver,” referring to the animal’s propensity for diving into deep foliage when threatened. The generic name of this species, Cephalophus, derives from the Greek words kephale, meaning “head” and lophus, meaning “crest,” referring to the tuft of hair found on top of the animal’s head. Finally, the name maxwellii was given to this species to honor Colonel Charles Maxwell, who captured the P. maxwellii specimen first described by Hamilton Smith in 1827. ("Cephalophus maxwelli", 1982; Ralls, 1973)

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Justin Skrzynski (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

crepuscular

active at dawn and dusk

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

folivore

an animal that mainly eats leaves.

food

A substance that provides both nutrients and energy to a living thing.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

frugivore

an animal that mainly eats fruit

herbivore

An animal that eats mainly plants or parts of plants.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

sexual ornamentation

one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.

solitary

lives alone

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

1982. Cephalophus maxwelli. Pp. 331 in J Honacki, K Kinman, J Koeppl, eds. Mammal Species of the World. Lawrence, Kansas: Allen Press, Inc. and The Association of Systematics Collections.

1999. "Cephalophus maxwellii" (On-line). African Mammals Databank. Accessed January 29, 2006 at http://www.gisbau.uniroma1.it/amd/amd337b.html.

2004. "Cephalophus maxwellii" (On-line). IUCN Red List of Threatened Species. Accessed March 17, 2006 at http://www.redlist.org/search/details.php?species=4142.

Coe, M. 1975. Mammalian Ecological Studies on Mount Nimba, Liberia. Mammalia, 39: 523-581.

Dorst, J. 1970. A Field Guide to the Larger Mammals of Africa. Boston: Houghton Mifflin Company.

Geerling, C., J. Bokdam. 1973. Fauna of the Comoé National Park, Ivory Coast. Biological Conservation, 5(4): 251-257.

Happold, D. 1987. The Mammals of Nigeria. Oxford: Clarendon Press.

Hofmann, T., H. Roth. 2000. Feeding preferences of duiker (Cephalophus maxwelli, C. rufilatus and C. niger) in Ivory Coast and Ghana. Mammalian Biology, 68: 65-77.

Huffman, B. 2003. "Cephalophus maxwellii" (On-line). The Ultimate Ungulate Page. Accessed March 17, 2006 at http://www.ultimateungulate.com/Artiodactyla/Cephalophus_maxwellii.html.

Kingdon, J. 1974. East African Mammals. Chicago: The University of Chicago Press.

Ralls, K. 1973. Cephalophus maxwellii. Mammalian Species, 31: 1-4.

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