Lateral bias to the leading limb in an olfactory social signal by male ring-tailed lemurs

Because ring-tailed lemurs (Lemur catta) show handedness during feeding, I investigated whether they also show lateral preference in the limbs used by males during scent marking. During a bout of marking, a male alternates a variable number of shoulder rubs and arm marks. It is a complex social signal that has both olfactory and visual components and is frequently part of intrasexual agonistic interactions. I used all-occurrences behavior sampling, manually recorded all totally visible bouts, and required a minimum of 50 bouts per animal. The subjects included six wild and four group-living captive male lemurs. I considered limb usage to be lateralized for each individual lemur if the frequency of use of one side was significantly above chance as determined by binomial z-scores at P<.05. I measured consistency of lateral preference by calculating handedness index (HI) scores for each individual. Overall, I recorded 1,583 bouts of scent marking, and 66% of the bouts began with shoulder rubbing. Eight of the 10 males showed a significant, moderately strong lateral preference for the lead limb in the first shoulder rub performed in a bout, and for six of these eight the preferred lead limb for shoulder rubbing was the left one. Six of the 10 males showed a significant but weak lateral preference in the first arm mark, and five of these preferred the opposite limb to that used for the first shoulder rub. Although the preferences were not at the population level, eight of the 10 lemurs showed a lateral bias in the lead limb used for a component of this complex social signal.     

Wolf scent marking with raised-leg urination

Raised-leg urinations were performed almost exclusively by dominant male and female wolves (Canis lupus). The alpha male and female in two captive groups showed full raised-leg urinations (RLUs) throughout the year. Each alpha male and female sniffed and marked on one another's marks frequently; however, the pair that bred did more marking and more double marking. They increased their marking frequency prior to and during the breeding season, decreased it at the time of parturition, while the female was in the den, and then increased to a moderate level when the female took part in pack activities again. Because the alpha pair was the principal sender and receiver of the message within the group, it is likely that double marks function to maintain and advertise the pair bond. Because the group that did not breed also did not double mark frequently, the presence of double marking in a captive group may be diagnostic of the viability of the group as a pack.     

Olfactory demarcation of territorial but not home range boundaries by Lemur catta

Over 350 h of observations were collected using focal animal sampling of scent-marking behavior by 2 troops of ring-tailed lemurs (Lemur catta) in the field in Madagascar. Although they did not mark any branch species preferentially, they did have preferred marking sites. Significantly more scent marks were deposited in the area of home range overlap between troops than in the area of exclusive use. However, few marks were deposited at the periphery of the area of overlap. Instead, the majority of the marks were in a narrow band within the area of overlap that coincided with the positions of intertroop confrontations. Female genital marks and male arm marks, as well as the accompanying male shoulder rubs thus appear to demarcate territorial borders.     

Population and territory stability of the Lemur catta at Berenty, Madagascar.

Several Lemur catta troops at Berenty, Madagascar have been censused repeatedly since 1963. In 1972, the entire reserve was censused. A recensus in 1975 showed that although some minor changes have occurred in the number of animals in individual troops, the population of the reserve as a whole, the core areas of the lemurs' territories, and their home range boundaries have all remained stable ever since the first complete census 3 years earlier.     

Tamarind tree seed dispersal by ring-tailed lemurs

In Madagascar, the gallery forests of the south are among the most endangered. Tamarind trees (Tamarindus indica) dominate these riverine forests and are a keystone food resource for ring-tailed lemurs (Lemur catta). At Berenty Reserve, the presence of tamarind trees is declining, and there is little recruitment of young trees. Because mature tamarinds inhibit growth under their crowns, seeds must be dispersed away from adult trees if tree recruitment is to occur. Ring-tailed lemurs are likely seed dispersers; however, because they spend much of their feeding, siesta, and sleeping time in tamarinds, they may defecate a majority of the tamarind seeds under tamarind trees. To determine whether they disperse tamarind seeds away from overhanging tamarind tree crowns, we observed two troops for 10 days each, noted the locations of feeding and defecation, and collected seeds from feces and fruit for germination. We also collected additional data on tamarind seedling recruitment under natural conditions, in which seedling germination was abundant after extensive rain, including under the canopy. However, seedling survival to 1 year was lower when growing under mature tamarind tree crowns than when growing away from an overhanging crown. Despite low fruit abundance averaging two fruits/m³ in tamarind crowns, lemurs fed on tamarind fruit for 32% of their feeding samples. Daily path lengths averaged 1,266 m, and lemurs deposited seeds throughout their ranges. Fifty-eight percent of the 417 recorded lemur defecations were on the ground away from overhanging tamarind tree crowns. Tamarind seeds collected from both fruit and feces germinated. Because lemurs deposited viable seeds on the ground away from overhanging mature tamarind tree crowns, we conclude that ring-tailed lemurs provide tamarind tree seed dispersal services.     

Olfactory demarcation of territorial boundaries by a primate--Propithecus verreauxi.

Field observations of a troop of sifaka revealed that they scent mark the boundary areas of their territory far more than they do the interior, both during normal daily movements and during battles between adjacent troops. They are active throughout the territory but spend more time and have a higher frequency of marking at the periphery.     

Scent marking as resource defense by female Lemur catta

Because ring-tailed lemurs (Lemur catta) are a female-dominant, female-philopatric species in which the females provide the majority of parental care and troop defense, resource defense is a possible function of female lemur scent marking. To test this hypothesis, I conducted three studies. First, I presented captive, individually housed females with a series of samples of female scent, each from a different female, to determine whether they would respond to those samples and discriminate between them. Second, I reanalyzed data from a focal animal study of four females in two adjacent troops in Berenty Reserve, Madagascar, to determine female marking rates before, during, and after the mating season, and to clarify the relationship among positions of feeding, intertroop defense, and scent marking. The third study was based on ad libitum observations of the sniffing and marking behavior of a troop in Berenty Reserve during a year when they traveled far out of their home range. The females in study 1 investigated female scent samples but provided no evidence that they discriminated between them. In study 2 the wild females marked throughout the study and did not limit their marking to the mating season. They deposited significantly more of their marks in a zone of confrontation with adjacent troops, where they also did the majority of their feeding, and they increased their rate of marking during agonistic intertroop confrontations. The females determined the positions of their scent marks and deposited the first mark in the majority of countermarking sequences. When the females traveled out of their defended range in study 3, they significantly decreased their rate of marking and increased their rate of sniffing spots but not marking them. All evidence gathered so far supports the hypothesis that one function of female ring-tailed lemur scent marking is to provide intergroup information that is then used to reinforce the border of the defended resource.     

Tradition in Lemur catta Behavior at Berenty Reserve,Madagascar

Lemur catta Troop D at Berenty Reserve has been studied intermittently for 35 years. During 90 hours of continuous sampling in August 1998, I observed and mapped troop movement and scent marking. I compared these observations with data from June, 1975. The core of Troop D1's 1998 home range is the same as for Troop D in 1975. Sixty-two percent of Troop D1's time in 1998 was spent in the 1975 home range, and 52% of their scent marks were placed in that 1975 home range. The remainder of their time was spent in an extension of their home range, which is now an area of confrontation with an adjacent troop. They used the same sleeping trees in the 2 years, and all of the 1998 scent marks deposited in the 1975 home range were placed in the same locations marked in 1975. The similarities in their use of space in 1975 and 1998 were remarkable.     

Ring-Tailed Lemur Home Ranges Correlate with Food Abundance and Nutritional Content at a Time of Environmental Stress

In order to determine whether ring-tailed lemurs (Lemur catta) adapt their ranging and select an optimal diet at a time of food shortage, we observed two adjacent troops in Berenty Reserve, Madagascar for over 250 h. The troops, created by a recent fission, ranged through closed canopy gallery forest next to a river and open forest away from the river. We conducted the study in September–October, 2000, normally a time of seasonally low resource availability, which was intensified by damage from a previous windstorm and recent drought. To examine the impact of environmental stress, we mapped their ranging patterns, intertroop encounters, feeding patches, siesta trees, and sleeping trees. We then correlated their ranging and feeding behavior with nutritional analyses of leaves and fruit from tamarind trees located in different parts of their ranges. One of the troops, D1A, ranged farther into open forest than previously. However, the range for troop D1B and the closed canopy portion of D1A's range were located in traditional positions for historical troops D and E. Both troops ate significantly more mature leaves from the tamarind trees in the closed canopy forest, where the leaves had significantly higher nutritional content (water and protein) than that of open forest samples. They fed on tamarind fruit significantly more often in the open forest away from the river, where it was more abundant. The lemurs selected a diet that maximized leaf water and protein and ranged where fruit was most abundant but at high energetic costs for troop D1A.