Eulemur rubriventer
Red bellied lemur

Eulemur rubriventer male and female^P1

Identification

Eulemur rubriventer is mid sized lemur, it is sexually dichromatic. The coat is mostly brown with a black tail. The males have white patches around the eyes. The females have much smaller (or non-existent) eye patches, and have a white belly. Infants are usually colored like adult females (even infant males).

Eulemur rubriventer at RNP

There are several E. rubriventer groups in the Talatakely Trail System at RNP. Perhaps the best time to visit to see E. rubriventer is from late March through May, this is when the guava is fruiting and the animals are easy to spot in the guava patches. This is also the mating season and you are more likely to see scent marking and other interesting behaviors.

The data given here come mostly from Deborah Overdorff's study groups from Vatoharanana (about 5km south of the main research cabin) (Overdorff 1996a), and from Debi Durham's study in Talatakely and Vato (Durham, 2000, personal communication).

Physical Characteristics

Head & Body Length (Mittermeier et al, 1994)	400mm (16in)
Tail Length (Mittermeier et al, 1994)	500mm (20in)
Weight (Kappeler, 1991)	2270g (80oz)	2140g (75oz)

Life History

E. rubriventer mates in May and gives birth in September-October (in Vato) and August (in Talatakely). Infants are carried across the thigh. Infants are weaned around 4-5months (at the time of greatest food availability, Wright 1999). Only the female carries the infant for the first 20-30 days, the male then starts to carry it, the female refuses to carry it around day 55 after which only the male carries it until day 100 (Overdorff 1996a). One infant (occasionally twins) is born per year. Siblings will also carry infants (though less frequently than the father). As infants mature the parents spend less time with them and their siblings spend more time. (Durham, personal communication).

E. rubriventer male^P2

Locomotion

Locomotion is mainly quadrupedal with some vertical clinging and leaping, even occasional bipedal movement. ^{.5Mb V1}, of course they leap ^{.9Mb V1.5}

Dagosto (Dagosto, 1995) reports that leaping is more frequent in the dry season than the wet (and conversely that walking is less frequent).

Diet & Feeding

E. rubriventer is primarily frugivorous at RNP ^{1.2Mb V2 1.5Mb V3 .3Mb V4}. They are also known to eat leaves, flowers, mushrooms, arthropods (sometimes rolling millipedes in saliva to detoxify them. Here an E.r. drools on and manipulates a millipede for several minutes before it finally escapes ^{2.8Mb V5}), and dirt.

They lick nectar out of flowers rather than eating the entire flower (as E. fulvus rufus would) and are therefore better pollinators than E.f.r. They eat more ripe fruit and fewer leaves than E. f. r. (Overdorff, 1996b)

Sex differences in feeding variables did not correlate with female energetic costs. (Overdorff, 1991)

A group of E. rubriventer always eat all in one patch

Food sharing

Food sharing has not been observed, though infants will beg.

Activity Pattern

E. rubriventer is cathemeral.

Predators

I can find few definite instances of predation on E.r. in the literature.

The fossa (Cryptoprocta ferox)

E. r. fur has been found in its scat. (Overdorff & Strait, 1995)

Presumably its predators are similar to those that prey on E.f.r.

Boa manditra

E.r. have been observed to be wary around Boas (Goodman et al, 1993)

Raptors

Have been observed to prey upon Eulemur fulvus (Goodman et al, 1993).

Other lemurs

Eulemur fulvus ssp. have been observed to eat infant Lemur catta  and infant conspecifics at Berenty (A. Jolly et al, 2000).

Man, dogs, and cats

Behavior

Dominance

There is no obvious dominance hierarchy in Eulemur rubriventer (Overdorff). Males will give females feeding priority, and females generally lead the group out of a patch. (Durham, personal communication)

Social structure

Groups are monogamous in nature with 2-5 animals per group. Other animals in a group are the offspring of the parents.

The home range area is 19ha.

Territoriality

Eulemur rubriventer groups defend their territories (Overdorff 1996a).

Play

Vocalizations

• sneeze alarm ^S1
• nervous tick (with tailwag) ^{1.2Mb V6}
• contact grunt ^S2
• strange evening sounds ^S3

E.r. male scent marks with foreheadP3

E.r. male scent marks female female crawls under himP4

Scent Marks

Males scent mark with their genitals and will also rub the tops of their heads ^{.3Mb V7} and their wrists into scent. Females only do genital marks. Males will overmark after females have marked. Males and females will mark each other during the mating season ^{1.8Mb V8 3.9Mb V9 1.2Mb V10}. (Durham, personal communication)

Other Behaviors

Geographic Range

Eulemur rubriventer is found in the rainforests of the east coast of Madagascar. (Mittermeier et al, 1994).

Comparison to E. fulvus rufus at RNP

These two congeners have a similar size and are both primarily frugivores, yet they are sympatric. They have a different social structure (E.r. is monogamous with small groups, while E.f.r. lives in large multi-male, multi-female groups). An E.f.r. group tends to eat in several adjacent patches at a time while an E.r. group will only eat in one. E.r. is territorial and actively defends its territory's boundaries, while several E.f.r. groups will have overlapping ranges. E.f.r. groups have much larger and very fluid home ranges. E.f.r. groups will travel further between patches than E.r. groups. In E.f.r. there is little male parental care, while in E.r. groups there is a great deal. (Overdorff 1996a)

Although born at the same time, E.r. develops faster than E.f.r. E.r. feeds lower in the canopy than E.f.r. (Durham, personal communication)

Taxonomy

Mammalia -> Primata (Strepsirrhini, Lemuriformes) -> Lemuridae (Lemurianae) -> Eulemur rubriventer

Dagosto, M, 1995 "Seasonal Variation in Positional Behavior of Malagasy Lemurs", International Journal of Primatology, 16:(5) 807-833

Goodman, SM, O'Conner S, Langrand O, 1993 "A review of predation on lemurs: Implications for the evolution of social behavior in small, nocturnal primates", Lemur Social Systems and their Ecological Basis, 51-66

IUCN Conservation Monitoring Centre, viewed in July 2000, "Threatened Animals of the World", IUCN Red List of Threatened Animals

Jolly, A. et al, 2000 "Infant killing, wounding and predation in Eulemur and Lemur", International Journal of Primatology, 21:(1) 20-40

Kappeler, PM, 1991, "Patterns of sexual dimorphism in body weight among prosimian primates", Folia Primatologica, 57:132-146

Mittermeier, Russell et al, 1994, The Lemurs of Madagascar, Conservation International

Overdorff, DJ, 1996a, "Ecological Correlates to Activity and Habitat use of two Prosimian Primates, Eulemur rubriventer and Eulemur fulvus rufus in Madagascar", American Journal of Primatology, 40:(4) 327-42

Overdorff, DJ, 1996b, "Ecological Correlates to Range use in red-bellied lemurs(Eulemur rubriventer) and rufous lemurs (Eulemur fulvus rufus) ", Lemur Social Systems and their Ecological Basis, 167-178

Overdorff, DJ, 1996c, "Ecological Correlates to social structure in two Lemur species in Madagascar", American Journal of Physical Anthropology, 100:(4) 487-506

Overdorff, DJ & Strait SG, 1995, "Life History and Predation in Eulemur rubriventer in Madagascar", American Journal of Physical Anthropology, 20(321): 164-165

Overdorff, DJ, 1991, "Ecological Correlates to Social Structure of two Prosimian Primates, Eulemur rubriventer and Eulemur fulvus rufus in Madagascar", Ph.D. dissertation, Duke University

Rowe, Noel, 1996, The Pictorial Guide to the Living Primates, Pogonias Press

Wright, P.C. 1999 "Lemur traits and Madagascar ecology: coping with an island environment." Yearbook of Physical Anthropology 42: 31-72.

Juvenile female E.r.^P5

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