Parental behavior and infant development in ruffed lemurs (Varecia variegata) in a northeast Madagascar rain forest

Abstract

Parental behavior and infant development of black and white ruffed lemurs (Varecia vuriegata) were studied on Nosy Mangabe Island in northeast Madagascar. Ruffed lemur females produced twins, prepared nests for neonates in the trees, transported infants by mouth, and parked them in the trees. During two consecutive birth seasons, the average birth rate for nine females was 0.58. Two females reproduced in one social group. Lactating females spent most of their time resting with their infants or foraging for food. Infants developed rapidly and were fully mobile by 3-4 months. No female reproduced successfully in 2 consecutive years. In 1988, infant mortality within 3 months of birth was very high (64%). Accidental falls may have been one major cause. Adults of both sexes, including a reproductive female, exhibited alloparental behavior such as guarding infants and nonmaternal nursing. Alloparental care may increase the likelihood of infant survival. Some of these observations are not compatible with the idea that ruffed lemurs live in small pair-bonded groups, as other researchers have suggested.

Monitoring Impacts of Natural Resource Extraction on Lemurs of the Masoala Peninsula, Madagascar

“…This supports an earlier study that showed a difference in birth rate between years for individual female Eulemur elsewhere in Madagascar (Overdorff et al, in review). Similarly, our findings support an earlier suggestion that Varecia successfully reproduces only once in two years in the wild (Morland 1990). This birth interval may be due to the fact that Varecia regularly give birth to several infants at once and often successfully raise more than one in the wild, which requires a greater expenditure of energy than for those prosimians who raise a single infant with an interbirth interval of one year (Tattersall 1982).…”

“…Reproductive success was then calculated for each group as the total number of infants born in the group, divided by half of the number of adults in the group. Varecia infants are born in the dry season around October, and remain in a nest for about 3 months following birth (Morland 1990). Varecia v. rubra infants were not generally observed during censusing before December; therefore, the 1993 infants were first observed early in 1994, and the 1994 infants were first observed in early 1995.…”

Ontogeny of long bone geometry in capuchin monkeys (Cebus albifronsandCebus apella): implications for locomotor development and life history

“…Among capuchin monkeys, the rapid decline in humeral and femoral GSF prior to ecological independence indicates that bone strength was maximal during early infancy and initial locomotor efforts, when the risk of falling from trees would be greatest. Field studies of several arboreal primate species, ranging from prosimians to apes, have shown that infants typically fall more than mature group mates, at times resulting in fatal injury (Carpenter 1934;van Lawick-Goodall 1967;Morland 1990;Dunbar & Badam 1998). As such, relatively greater bone strength early in life could adaptively mitigate the risk of skeletal injury from falling.…”

Infanticide risk and the evolution of male–female association in primates

“…InVarecia, a 3.5 kg diurnal lemur, pregnant females build nests for their infants, in which they leave them during the ¢rst 1^2 weeks of life, and park them outside nests for 3^4 months thereafter (Morland 1990). Nonetheless, Varecia shows permanent male^female association (Morland 1991;Rigamonti 1993).…”