GUENONS - Management Guidelines for the Welfare of Zoo Animals
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ALLEN'S SWAMP MONKEY - BIOLOGY AND FIELD DATA

(Linked in Wildpro to species page Allenopithecus nigroviridis - Allen's swamp monkey (Link page only))

A: BIOLOGY

1.1 Taxonomy
1.2 Morphology
1.3 Physiology
1.4 Longevity

1.5 Zoogeography/Ecology
1.6 Diet and Feeding Behaviour
1.7 Reproduction
1.8 Behaviour

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1.1 Taxonomy - Allen's swamp monkey

Genetic (e.g. Ruvolo 1988; Dutrillaux et al., 1988) and morphological evidence (e.g. Kingdon, 1988; Martin & MacLarnon, 1988) strongly suggests that of all the guenon species, this one bears the closest resemblance to the 'ancestral' guenon.

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SIZE

Allen’s swamp monkeys are more baboon-like, have a shorter body and tail, and are more muscular, than other guenon species. The females are smaller than the males, and are less robust (Hill, 1966).

COLORATION

This monkey is a drab khaki colour (Kingdon, 1980). The crown, nape of neck, shoulders, centre of the back, and dorsal part and tip of the tail are black with yellow speckles. Limbs are speckled like the back, but more golden, and the thighs are greyish towards the feet. Underparts are paler speckled black and yellow, except for a dark shade across the breast, and a rusty red area near the flanks. The throat is light grey, face and ears dark grey-brown with a black band of stiff hairs over the eyes, which narrows towards the ears (Hill, 1966). The chin is pink-white with stiff grey-white hairs, and the fur on the cheeks is exceptionally long forming a broad ruff, and a ridge over the curve of the cheek (Kingdon, 1980). The neonate resembles the adult, but is more golden. The head is almost white, and blends with the mother’s pale throat ruff for concealment (Hill, 1966).

DESCRIPTION

(See L’Hoest’s monkey Management Guidelines - Guenons - Section 1 (L'HOEST'S MONKEY - BIOLOGY AND FIELD DATA) for general information). Pelage is coarse above, softer and sparser below (Hill, 1966). Ears are more pointed at the top than in other guenons, and the stomach differs from other guenons in its 'incipient' sacculation (similar to that of the Colobines) (Hill, 1966). They may also have a specialised cutaneous glandular area in the sternal region of the chest as in the De Brazza’s monkey (see Hamlyn’s monkeys Management Guidelines - Guenons - Section 1 (HAMLYN'S (OWL-FACE)  MONKEY - BIOLOGY AND FIELD DATA), and Kingdon, 1988).

VOICE

(See L’Hoest’s monkey Management Guidelines - Guenons - Section 1 (L'HOEST'S MONKEY - BIOLOGY AND FIELD DATA) for general information). A number of calls and their social implications have been described by Gautier (1988). The warning call in this species is described as single 'chirps' and the loud rallying call of the male as a 'gobble'.

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1.3 Physiology - Allen's swamp monkey

Unknown.

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1.4 Longevity Allen's swamp monkey

(See L’Hoest’s monkey Management Guidelines - Guenons - Section 1 (L'HOEST'S MONKEY - BIOLOGY AND FIELD DATA) for general information).

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DISTRIBUTION

(See L’Hoest’s monkey Management Guidelines - Guenons - Section 1 (L'HOEST'S MONKEY - BIOLOGY AND FIELD DATA) for general information). Allen’s swamp monkeys are found on the left bank of the Zaire river (Gautier, 1985), and on the banks of the Ruki/Tshuapa river basin, though they are not found on the right bank of the Zaire river, or along the Lualaba river (Colyn, 1988). They are common along the right bank tributaries of the Lopori river, and can probably be found along the Loia. The left bank of the Lomami is the eastern limit for this species (Colyn, 1988). It has been suggested that they reach as far north as the south bank of the Ubangi/Uelle rivers (4 degrees north), and as far south as the Fini river (Hill, 1966), however, Gautier (1985) extended their southern limit to 6 degrees thirty minutes south from the report of a local hunter. The western limit has been suggested as following the Fini and Kasai rivers to its confluence with the Zaire river, which it crosses (Hill, 1966). Malbrant & Maclatchy (1949) suggested that the range of this species includes the lower Likousla-Massaka and lower Sangha basins. Gautier (1985) gave east and west distribution range limits of 16 degrees East, and 26-27 degrees East, and stated that Allen’s monkeys are abundant in Mbandaka, Gemena, Mondombe, and Lisale.

HABITAT

The range of these monkeys is largely restricted to areas of swamp forest on river banks (Colyn, 1988), on islands in the river Zaire, and Lake Leopold II area (Hill, 1966). However, in the Lomako forest they are found in both swamp and gallery forest (Zeeve, 1985), and can also be found in regularly flooded forest (Malbrant & Maclatchy, 1949; Cords, 1987). The climate is hot and humid, with annual rainfall of less than 2m limited to two rainy seasons: March to May, and October to November. Allen’s swamp monkeys inhabit the lower strata and can mainly be found less than 5m from the ground (Gautier-Hion, 1988b). The percentage use of strata is as follows: -

LOWER (<10m) 90%

MIDDLE (10-20m) 10%

(Gautier, 1985)

POPULATION AND CONSERVATION STATUS

Lomako Forest has within it a study area where an agreement with the local people restricts the hunting of primates. However, Allen’s swamp monkeys are regarded highly by natives as food, and elsewhere hunters set traps for them on the forest floor, and hunt them with bows and arrows (Zeeve, 1985). Allen’s swamp monkey is listed as near threatened (List 3) in the IUCN Red List of Threatened Animals (1996).

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1.6 Diet and Feeding Behaviour - Allen's swamp monkey

FOOD PREFERENCE

(See L’Hoest’s monkey Management Guidelines - Guenons - Section 1 (L'HOEST'S MONKEY - BIOLOGY AND FIELD DATA) for general information). The proportion of foods taken is as follows:-

FRUIT                     81%

LEAF MATTER        2%

PREY                      17%

(Gautier, 1985)

Small fish, shrimp, and snails are included in the diet as well as fruits, nuts, seeds, and insect larvae (Pournelle, 1959; Zeeve, 1985). Wild ginger (F. Maisel, pers. comm.²), pith and roots, beetles, and worms are also eaten (Zeeve, 1985).

FEEDING

(See L’Hoest’s monkey Management Guidelines - Guenons - Section 1 (L'HOEST'S MONKEY - BIOLOGY AND FIELD DATA) for general information). Fruits are taken from low trees or bushes, and much plant and insect food is gathered on the ground. The monkeys walk along river-beds in the dry season to scoop up fish hatchlings from muddy pools in the evening and pre-dawn hours (Zeeve, 1985). Troops near villages dig up tubers from Cassava plantations (Gautier, 1985).

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1.7 Reproduction - Allen's swamp monkey

SEXUAL MATURITY

(See L’Hoest’s monkey Management Guidelines - Guenons - Section 1 (L'HOEST'S MONKEY - BIOLOGY AND FIELD DATA) for general information).

BREEDING CYCLES

(See L’Hoest’s monkey Management Guidelines - Guenons - Section 1 (L'HOEST'S MONKEY - BIOLOGY AND FIELD DATA) for general information). Female Allen swamp monkeys, unlike most other guenons, have a moderate catamenial swelling (Hill, 1966; Loy, 1987). Swelling of the perineum is a morphological reproductive cycle which is closely correlated with the menstrual cycle and its various hormones (Loy, 1987). It has been studied extensively in baboons, where maximum turgescence coincides with the pre-ovulatory period, and de-turgescence is thought to begin approximately 3 days after ovulation (Hausfater, 1975).

Among African monkeys, those showing monthly swellings come closest to showing oestrous behaviour, i.e. mating only at that point in the menstrual cycle when the female is most likely to conceive. Miopithecus talapoin Talapoin males mate mostly with females at full turgescence, though they have been seen mating with females at all other stages of the swelling cycle (Loy, 1987). In baboons the dominant males mate almost exclusively with fully turgescent females, though juvenile and sub-adult males mate with females at other stages of the cycle (Loy, 1987). Nothing is documented on the mating behaviour of Allen’s swamp monkeys; however we can perhaps assume a similarity to these two species.

DEVELOPMENT

(See L’Hoest’s monkey Management Guidelines - Guenons - Section 1 (L'HOEST'S MONKEY - BIOLOGY AND FIELD DATA) for general information).

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1.8 Behaviour - Allen's swamp monkey

ACTIVITY

(See L’Hoest’s monkey Management Guidelines - Guenons - Section 1 (L'HOEST'S MONKEY - BIOLOGY AND FIELD DATA) for general information). These monkeys are extremely competent swimmers and divers (Zeeve, 1987). Sleeping sites are situated on river banks, the same sites are occupied regularly (Gautier, 1985). Allen’s monkeys may move distances of 110-2,400m to get to sleeping trees. Once there, they spread out over 100m in smaller groups. Sleeping sites are entered between 5.30-6.30pm and are left at dawn (Gautier, 1985).

PREDATION

When confronted by a predator, these monkeys utter a call which spreads through the group. Mobbing of, or flight from, the predator follows, dependant on the situation. Allen’s swamp monkeys flee over the ground, or dive into the water to escape (Gautier-Hion, 1988b), descending from trees if necessary (Zeeve, 1985).

SOCIAL BEHAVIOUR

(See L’Hoest’s monkey Management Guidelines - Guenons - Section 1 (L'HOEST'S MONKEY - BIOLOGY AND FIELD DATA) for general information). There is some controversy as to the group structure of Allen’s swamp monkeys in the wild. Zeeve (1985) stated that they travel in bands of 2-6 monkeys, and Gautier (1985) and Gautier-Hion et al., (1988) state that they spend the day in large multi-male troops of over forty animals, with group cohesion during travel being limited (Gautier, 1985). F. Maisel (pers. comm.²) observed several groups joining together to sleep at night in a group of up to 100 animals. A study on captive Allen’s swamp monkeys showed that allo-grooming is less important than in, for example, Hamlyn’s monkeys, this behaviour taking only 5-7% of the monkeys' time (Phillips, 1992). It was mentioned previously (see Hamlyn’s monkeys Management Guidelines - Guenons - Section 1 (HAMLYN'S (OWL-FACE)  MONKEY - BIOLOGY AND FIELD DATA)) that those species with a rigidly maintained dominance hierarchy show more allo-grooming. The results of this study therefore tend to support the idea of a large multi-male group with a more relaxed dominance structure, rather than that of a small one male group with defined relationships between each member. Scent marking, thought to have a social role, has also been seen in this species in captivity in a similar form to that studied in captive De Brazza’s monkeys (Loireau & Gautier-Hion, 1988, and see Hamlyn’s monkeys Management Guidelines - Guenons - Section 1 (HAMLYN'S (OWL-FACE)  MONKEY - BIOLOGY AND FIELD DATA)).

Threats directed within the group take the form of 'pseudo charges' with the mouth open and teeth bared, the same facial expression sitting down, or a display involving leaping onto a branch and pushing it with the feet to produce a loud crash (Phillips, 1992). As with many mammals, a direct stare in guenons is likely to precipitate aggression. The ridge of fur over the cheek of Allen’s swamp monkeys allows discrete monitoring of other members of the group, as does lowering the head and watching from under the brow ridge. These monkeys also attempt to avoid aggression by moving the head as though the animals were watching something fast flying overhead, a highly ritualised advertisement of eye contact cut-off resulting in a flash of white (Kingdon, 1988).

SOCIAL DEVELOPMENT

(See L’Hoest’s monkey Management Guidelines - Guenons - Section 1 (L'HOEST'S MONKEY - BIOLOGY AND FIELD DATA) for general information).

SEXUAL BEHAVIOUR

(See L’Hoest’s monkey Management Guidelines - Guenons - Section 1 (L'HOEST'S MONKEY - BIOLOGY AND FIELD DATA) for general information).