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PubMed1993

The vocal repertoire of the ringtailed lemur (Lemur catta).

The vocal repertoire of the ringtailed lemur (Lemur catta) is described quantitatively and spectrographically. Structure, usage and inferred function of the vocalizations of adults and immatures are examined and discussed. The size, acoustic variability and development of the ringtailed lemur's vocal repertoire are compared to prior assessments for this species as well as for other primates. With up to 22 different adult call types, the ringtailed lemur has a moderately large vocal repertoire for a primate.

Aging↗
PubMed1998

Trypanosoma cruzi infection of free-ranging lion-tailed macaques (Macaca silenus) and ring-tailed lemurs (Lemur catta) on St. Catherine's Island, Georgia, USA.

Free-ranging Old World primates released on St. Catherine's Island, Georgia (USA), were tested for infection with Trypanosoma cruzi as part of a study of the epizootiology of sylvatic T. cruzi in the southeastern USA. The parasite was observed in liver infusion tryptose medium cultures of blood from seven of 11 lion-tailed macaques (Macaca silenus) and one of 19 ring-tailed lemurs (Lemur catta). Cultures of blood from 10 black and white ruffed lemurs (Varecia variegata) were all negative. Analysis of small subunit ribosomal RNA gene polymorphisms detected using polymerase chain reaction techniques indicates that the parasites isolated from both the lion-tailed macaques and the ring-tailed lemur are probably the same as T. cruzi parasites isolated from raccoons (Procyon lotor) trapped on St. Catherine's Island and other locations in the southeastern USA. Foraging lion-tailed macaques were observed to handle and partially consume specimens of Triatoma sanguisuga, the triatomine bug thought to be a vector of T. cruzi in the southeastern USA. Oral transmission of the parasite may have occurred as a result of this behavior.

Animals↗
PubMed1999

Preventing dental calculus formation in lemurs (Lemur catta, Eulemur fulvus collaris) and baboons (Papio cynocephalus).

The prevention of calculus accumulation in exotic animals is a relatively unexplored topic. A 6-mo study in ring-tailed lemurs (Lemur catta) and collared lemurs (Eulemur fulvus collaris) and two studies in baboons (Papio cynocephalus) (7.5 wks and 6.5 mo) tested the benefits of a primate diet coated with 0.6% sodium hexametaphosphate (HMP) in controlling calculus in these species using a sequential crossover design. The control regimen was an identical, but non-HMP-coated, dry primate chow. At study initiation, the primates were given a thorough dental prophylaxis and provided with the control diet or experimental diet. At the conclusion of the test period, the animals were anesthetized and examined for clinical calculus independently by two examiners. The animals were then given another dental prophylaxis, provided the alternate ration, and the foregoing procedures were repeated. When the animals were provided the HMP-coated diet, significant reductions in calculus formation of 48-62% were observed in the lemurs and the baboons. No clinically significant changes were observed in body weights or in blood chemistry values as a result of ingestion of the HMP-coated regimen.

Animal Feed↗
PubMed2006

Troop fission in wild ring-tailed lemurs (Lemur catta) at Berenty, Madagascar.

A detailed fission process in a wild ring-tailed lemur (Lemur catta) troop was observed at Berenty Reserve, Madagascar. The troop fission occurred as follows: 1) During the birth season in 2000, two adult females (mother and daughter) were evicted as a result of "targeted aggression" (i.e., intense and persistent aggressive behavior toward particular individuals). 2) Two adult and three immature females in the same kin group as the evicted females spontaneously immigrated into the new group. 3) A male immigrated into the new group 1.5 months later. 4) The new troop successfully established its own home range. This report exemplifies three characteristics of troop fission in ring-tailed lemurs. First, targeted aggression initiated the fission process. Second, the troop females divided along matrilineal lines. Finally, no male played a specific role in the fission process.

Aggression↗
PubMed2003

Female dominance status and fecal corticoids in a cooperative breeder with low reproductive skew: ring-tailed lemurs (Lemur catta).

Many studies have shown that low dominance status within a social group is associated with elevated glucocorticoid hormone production, a common index of physiological stress. However, the reverse may be true among cooperatively breeding female mammals with high reproductive skew; that is, high dominance status is associated with elevated glucocorticoid levels. Elevated glucocorticoid levels in these dominant females may be a product of their being the only breeder within a group or may result from other challenges associated with high status. To test this difference, we studied fecal corticoid levels in cooperative breeding females with low reproductive skew (i.e., where reproduction is not limited to dominant group members): ring-tailed lemurs (Lemur catta). We collected behavioral and fecal corticoid data from 39 ring-tailed lemur females from eight groups across three sites. In seven of the eight groups, either one or both of the two most dominant females (ranks 1 and 2) exhibited the highest fecal corticoid levels in the groups. The best predictor of corticoid levels in high-ranking females was the proportion of aggressive agonistic interactions they initiated. For the lower-ranking females the best predictors of elevated corticoid levels were being the recipient of aggressive attacks and being relatively close to one's nearest neighbors. These results differ from many studies of caged male mammals where subordinate individuals often exhibit the highest glucocorticoid levels of a group. Furthermore, the results indicate that reproduction itself is not the primary reason for higher glucocorticoid levels among dominant cooperative-breeding females, but that some other factor must account for these elevated levels.

Aggression↗
PubMed2006

Can lemurs learn to deceive? A study in the black lemur (Eulemur macaco).

Deceptive behavior in primates has been the focus of a number of studies. Nevertheless, such abilities have never been demonstrated in prosimians. The authors' goal was to analyze possible deception in lemurs according to a paradigm used with simians. Three black lemurs were trained to communicate about the location of a hidden reward with a cooperative trainer. Afterward, when a 2nd trainer and lemurs competed to gain access to the reward, each subject differentially adapted its learned behavior to the context. Their performances with the cooperative trainer remained stable while they showed various behavioral adjustments when faced to the competitive trainer: 1 subject refused to participate, another preferentially withheld information, and the 3rd sometimes pointed deceptively to obtain the reward.

Adaptation, Psychological↗
PubMed2005

How prosimian primates represent tools: experiments with two lemur species (Eulemur fulvus and Lemur catta).

The authors examined how 2 lemur species (Eulemur fulvus and Lemur catta) reason about tools. Experiment 1 allowed subjects to use 1 of 2 canes to retrieve an inaccessible food reward. Lemurs learned to solve this problem as quickly as other primates. Experiment 2 then presented subjects with novel tools differing from the originals along one featural dimension. Subjects attended more to tools' sizes than to their colors and made no distinction between tools' shapes and textures. Experiments 3 and 4 presented problems in which some of the tools' orientations had to be modified relative to the food. Subjects performed well on these problems, sometimes modifying the position of the tool. These results are discussed in light of the performance of other primates on this task.

Animals↗
PubMed1977

Chromosomal evolution in Malagasy lemurs. II. Meiosis in intra- and interspecific hybrids in the genus Lemur.

The chromosome analysis of meiosis in four lemurs, Lemur fulvus fulvus, L. f. collaris, L. f. albocollaris, and L. macaco, and particular hybrid crosses is reported. In metaphase I, trivalents and chain elements were detected and identified with T-banding. The study largely confirms our previous work on mitotic karyotype comparisons in the genus Lemur. The absence of chain multivalents elements in the pachytene stages of hybrid meiosis, where a chain is detected later in diakinesis, may offer evidence on the possible existence of a two-step pairing mechanism in meiotic homolog pairing. Considerations about the role of the chromosome rearrangements in establishing a gametic barrier in speciation are developed.

Animals↗
PubMed1977

Aspects of reproduction in ruffed lemurs (Lemur variegatus).

Results of breeding of ruffed lemurs (Lemur variegatus) at the Duke Primate Facility provide information concerning estrous cycle, sexual behavior, age of first conception, gestation period, parturition, litter size. L. variegatus differs from other Lemur species in these respects.

Animals↗
PubMed1985

Habitat separation of semifree-ranging Lemur catta and Lemur fulvus.

Habitat use of two semifree-ranging groups of lemurs, Lemur catta and Lemur fulvus, was studied in relation to abiotic, floristic, and structural characteristics of their enclosure. L. catta was very flexible in the use of the habitat and showed a tendency for random utilization. But this species reacted quickly to changes of the abiotic environment. L. fulvus preferred to stay in areas with dense vegetation but good lateral visibility and close to the food plants. Abiotic factors such as solar radiation and ambient temperature influenced L. fulvus to a lesser extent than L. catta. According to these results L. catta could be considered to be adapted to variable environments where it is advantageous to react quickly to changes of abiotic factors. The conservative habitat use and the limited response to abiotic factors of L. fulvus might reflect adaptations of a species living in a stable environment. If these interpretations prove correct, then this study provides another example of animals born and raised in captivity that have retained habitat preferences of their wild conspecifics.

Animals↗
PubMed1986

Population ecology of the ring-tailed lemur, Lemur catta, and the white sifaka, Propithecus verreauxi verreauxi, at Berenty, Madagascar, 1981.

The diurnal lemurs Propithecus verreauxi verreauxi and Lemur catta at Berenty in southern Madagascar, have been studied for the last 30 years. The August 1981 census indicates that the population size of L. catta remains stable at 150 adults but that P. v. verreauxi troops have become fragmented and scattered and the population is apparently increasing. Eight different vegetation types were classified within the reserve and their influence on the distribution of L. catta and P. v. verreauxi investigated. Behavioural data obtained shows the niche separation between these two, potentially competitive, sympatric lemurs.

Animals↗
PubMed2000

T-cell-rich B-cell lymphoma in a ring-tailed lemur (Lemur catta).

A 13-yr-old ring-tailed lemur (Lemur catta) was evaluated for depression, anorexia, polyuria, and polydipsia. The lemur was in poor body condition and was anemic, hypoalbuminemic, and hyponatremic. Cytologic examination of aspirates of the spleen, liver, and bone marrow and histopathologic examination of liver and bone marrow biopsies revealed a disseminated round cell tumor. After euthanasia, necropsy revealed hepatomegaly, splenomegaly, and mesenteric lymphadenomegaly. Neoplastic cells were present within the spleen, liver, kidneys, multiple lymph nodes, bone marrow, lung, small intestine, pancreas, and testicle and were composed of large anaplastic round cells in a background of small well-differentiated lymphocytes. Immunohistochemical analysis revealed that the small well-differentiated lymphocytes labeled for the anti-human T-cell marker, CD3, and the large anaplastic round cells labeled with the anti-human B-cell marker, CD79a. On the basis of the immunohistochemical staining results and morphologic appearance, a diagnosis of a T-cell-rich B-cell lymphoma was made.

Animal Diseases↗
PubMed2003

Biomedical evaluation of free-ranging ring-tailed lemurs (Lemur catta) in Tsimanampetsotsa Strict Nature Reserve, Madagascar.

Complete health assessments were performed on 20 adult ring-tailed lemurs (Lemur catta), 10 males and 10 females, free ranging within the Tsimanampetsotsa Strict Nature Reserve in southwest Madagascar. Each animal was anesthetized using tiletamine and zolazepam, weighed, and given a thorough physical examination. Blood was collected for hematology, determination of plasma total protein concentration, serum chemistry, determination of fat-soluble vitamin and trace mineral concentrations, assessment of iron metabolism, toxoplasmosis and viral serologies, and examination for parasites. Feces were collected for bacterial culture and parasite examination, and representative numbers of ectoparasites were collected. Blood values differed significantly in a number of ways from values in captive lemurs, possibly associated with recent food consumption, hydration, and diet. There was no evidence of serious infectious disease and no hemoparasites. The enteric flora appeared unremarkable, although results may have been skewed toward cold-tolerant bacteria. The fecal parasite burden was low, but there were large numbers of ectoparasites (mites) present. Our study demonstrated that a substantial amount of data can be collected from free-ranging populations, information that is invaluable in the management of captive populations, particularly with regard to disease, and in assessing risks associated with reintroduction programs.

Animals↗
PubMed1985

Arboviruses and lemurs in Madagascar: experimental infection of Lemur fulvus with yellow fever and West Nile viruses.

In previous serological surveys of lemurs in Madagascar, antibodies against flaviviruses were frequently detected. To examine the epidemiological role of Lemur fulvus, experimental infections with yellow fever (YF) virus and West Nile (WN) virus were performed. YF and WN infections were clinically unapparent. A 3 to 4-day-long viremia, with moderate levels was observed with YF virus. WN virus, especially the strain isolated in Madagascar, provoked a 4 to 6-day-long viremia sufficient to infect Aedes aegypti. In all experiments, the antibody response was studied during the following weeks by 3 methods. The results led to the conclusion that Malagasy lemurs could act as amplifying hosts for WN virus present in Madagascar, and as hosts for YF virus if it were introduced on the island. The epidemiological role of these primates is discussed according to their ecology and their contact with potential mosquito vectors in forest areas of Madagascar.

Aedes↗
PubMed1979

Amino acid sequences of the alpha and beta chains of adult hemoglobin of the brown lemur, Lemur fulvus fulvus.

Globin prepared from hemoglobin of the brown lemur (Lemur fulvus fulvus) was separated into alpha and beta chains by chromatography on a CM 52 column. The S-aminoethylated alpha and beta chains were each digested with trypsin and resulting peptides were isolated. The amino acid sequences of the tryptic peptides were established. The ordering of these peptides in the alpha and beta chains was deduced from the homology of their amino acid sequences with that of human adult hemoglobin. The primary structure of brown lemur hemoglobin thus obtained differs from that of human hemoglobin in 15 amino acids in the alpha chain and 26 in the beta chain.

Amino Acid Sequence↗
PubMed1991

[Reactions to mirror in three species of lemurs (Lemur fulvus, L. macaco, L. catta)].

Reactions when confronted with their own reflection in a mirror were observed in three captive groups of lemurs: L. fulvus, L. macaco and L. catta. The ability of a mirror to induce social facilitation of drinking was also studied in one individual of each species. As previously observed in monkeys, the three groups of lemurs showed much more attention to the mirror than to a non-reflective surface, especially nasal contacts. Only L. fulvus showed habituation to the mirror with successive presentations. No social behaviours were directed towards the reflection, in contrast to descriptions of mirror-image reactions in monkeys, and the mirror did not produce an effect of social facilitation. The results suggest that the mirror elicits a diminished social reaction in lemurs compared to monkeys, perhaps due to the absence of relevant olfactory stimuli.

Animals↗
PubMed2005

Expectations about numerical events in four lemur species (Eulemur fulvus, Eulemur mongoz, Lemur catta and Varecia rubra).

Although much is known about how some primates--in particular, monkeys and apes--represent and enumerate different numbers of objects, very little is known about the numerical abilities of prosimian primates. Here, we explore how four lemur species (Eulemur fulvus, E. mongoz, Lemur catta, and Varecia rubra) represent small numbers of objects. Specifically, we presented lemurs with three expectancy violation looking time experiments aimed at exploring their expectations about a simple 1+1 addition event. In these experiments, we presented subjects with displays in which two lemons were sequentially added behind an occluder and then measured subjects' duration of looking to expected and unexpected outcomes. In experiment 1, subjects looked reliably longer at an unexpected outcome of only one object than at an expected outcome of two objects. Similarly, subjects in experiment 2 looked reliably longer at an unexpected outcome of three objects than at an expected outcome of two objects. In experiment 3, subjects looked reliably longer at an unexpected outcome of one object twice the size of the original than at an expected outcome of two objects of the original size. These results suggest that some prosimian primates understand the outcome of simple arithmetic operations. These results are discussed in light of similar findings in human infants and other adult primates.

Animals↗
PubMed1997

Affiliative relationships between adult males and immature group members in naturally occurring ringtailed lemurs (Lemur catta).

Affiliative relations between adult males and immature group members were studied in three naturally occurring groups of ringtailed lemurs (Lemur catta) over a 12-month period at Beza-Mahafaly Reserve, southwestern Madagascar. No statistically significant difference was found in rates of affiliative interactions between adult males and older immatures (juveniles and adolescents) over reproductive seasons. However, some of the adult males in two focal groups increased their rates of affiliative behaviors with older immatures during the lactation and subsequent 1993 postmigration periods. Female involvement with infants during lactation season, the increasing independence of juveniles and adolescents, and length of male tenure may be factors contributing to such a pattern. Neither adult males nor immatures were significantly responsible for the initiation and maintenance of proximity in male-immature dyadic interactions. Neither dominance rank nor age-class of the adult male affected their rates of affiliative behavior with immatures. The majority of focal males exhibited an interest in infants and occasionally participated in alloparental care. It is suggested that adult males can benefit from affiliative relations with immatures in terms of opportunities for greater spatial centrality in the group, which can lead to enhanced predator protection and greater opportunities to develop affiliative relationships with females. Immatures can benefit from affiliation with males in relation to enhanced predator detection and protection, alloparental care, and opportunities to develop social skills.

Age Factors↗