Gray Gentle Lemur (Hapalemur griseus)


MORPHOLOGY:
The average body mass for adult males is 748 grams and for adult females is 670 grams (Fleagle, 1999). In this species the forelimbs are shorter than the hindlimbs. The front teeth are specially developed for eating bamboo, with a dental formula of 2:1:3:3; they also have a dental comb used for grooming. Females possess one pair of mammae (Tattersall, 1982).

This species has four subspecies each having their own pelage coloration:

*Note that Groves (1988, 2001) elevates Hapalemur griseus alaotrensis and Hapalemur griseus occidentalis to full species status.

RANGE:
This species is found in Madagascar in areas with bamboo, marshlands and other forests in areas of high humidity. At Reserve Speciale d'Anjanaharibe-Sud, the gray gentle lemur is found at altitudes between 1260 and 1950 meters (Schmid and Smolker, 1998). At Ambatovaky Special Reserve this species lives in primary lowland forest, moist montane forest, and sclerophyllous montane forest between altitudes of 400-1000 meters (Evans et al., 1993-1994).

This species has four subspecies each having their own range:

This species is found in the following protected areas in Madagascar (Schmid and Smolker, 1998; Evans et al., 1993-1994):

ECOLOGY:
This species primarily eats the stem of the bamboo plant, but bamboo leaves, grasses, leaves, seeds, and fruit are also eaten. The parts of the bamboo plant that are consumed are mainly the young leaf shoots and the inner walls of the culm shoots (Stafford et al., 1993). In captivity the gray gentle lemur was found to select foods that were poor in fibre but rich in protein (Leclerq and Santini-Palka, 1995; Fidgett et al., 1996). At Ranomafana National Park from June to August, the diet of this species was found to primarily be of bamboo (98%) (Wright et al., 1987). At Analamazoatra Special Reserve bamboo of the genus Bambusa made up 90% of the diet, but fig leaves, leaf stems of terrestrial grass, young leaves from trees, small berries of the understory, and soil were also consumed (Wright, 1986). In the northern highland regions of Marojejy and Tsaratanana the bamboo species Ochlandra capitata, Phyllostachys aurea, and Dendrocalamus giganteus are important part of the diet for gray gentle lemurs living there (Pollock, 1986). The subspecies Hapalemur griseus alaotrensis has been found to consume the leaves and shoots of the genus Phragmites and the buds and pith of the genus Papyrus (Petter and Peyrieras, 1975). At Analamazoatra Special Reserve this species has been observed to consume surface grasses, fig leaves, and fruit in addition to bamboo (Pollock, 1986). In the western part of its range, this species has been observed to eat fruit from the species Flacourtia ramontchi (Pollock, 1986). Seeds of the genus Dypsis have been found in the faeces of the gray gentle lemur (Pollock, 1986). The feeding and ranging pattern of the gray gentle lemur may be affected by the frequency and distribution of liana bamboo (Grassi, 1998). When feeding on side of the mouth is preferred for removing a bamboo shoot and the other side for mastication (chewing) (Stafford et al., 1993). There is individual lateralization of hand preference when feeding in this species (Stafford et al., 1993). The subspecies Hapalemur griseus griseus was found to consume bamboo stalks by first pulling them to the mouth by hand and then tearing off the exterior layers with the anterior cheek teeth (Schmid and Smolker, 1998; Santini-Palka, 1994). The base of young bamboo leaves are extracted by the mouth, but transferred to the hand before consumption (Petter and Peyrieras, 1975).

Tan (1999) found that at Ranomafana National Park the diet of this species was composed of giant bamboo, Cathariostachys madagascariensis (72%), other bamboo and grass species (16%), nonbamboo foliage (4%), fruit (5%), and other (3%). The parts of the bamboo plant eaten include: the young leaf bases, the immature part of pseudopetioles, branch shoots (new sprouts from the nodes), and shoots (new sprouts from the subterraneous rhizomes) (Tan, 1999). Four bamboo species were utilized: Cathariostachys madagascariensis, Cephalostachyum cf. perrieri, Cephalostachyum cf. viguieri, and Nastus elongatus (Tan, 1999). Nonbamboo foliage primarily came from lianas as compared to trees (Tan, 1999). Fruit eating tends to be opportunistic, occurring during the summer months when fruits are abundant (Tan, 1999). This species was found on guava plantations during the fruiting season (Tan, 1999).

Overdorff et al. (1997) found that at Ranomafana National Park the majority of the diet of the gray gentle lemur consisted of two species of bamboo lianas and Cephalostachyum perrieri (89.1%). This species also fed on fruits (1.2%), fungus (0.5%), mushrooms (1.4%), leaf petioles (0.6%), flowers (0.4%), and new leaves (0.3%) (Overdorff et al., 1997). New leaf and flower feeding was found to occur only in October and November (Overdorff et al., 1997). Cephalostachyum perrieri tends to be consumed more in the first wet season than the second wet season (Overdorff et al., 1997). Bamboo liana species are consumed more than Cephalostachyum perrieri during both dry seasons (Overdorff et al., 1997). Groups here were found to spend more time feeding during the cooler, drier months as opposed to the warmer, wetter months (Overdorff et al., 1997). Dietary diversity increased towards the end of the dry season which corresponds to the time when females are gestating (Overdorff et al., 1997).

In southeastern Madagascar it was found that group sizes for this species ranged from 3-4 individuals (Wright et al., 1987). The subspecies Hapalemur griseus griseus was found to live in groups of 2-5 individuals, but larger aggregations can occur (Pollock, 1986). The subspecies Hapalemur griseus alaotrensis was found to live in groups ranging from 2-6 individuals, with a mean of 3.3 individuals (Nievergelt et al., 1998a). At Ambatovaky Special Reserve the mean group size for this species was found to be 2.6 individuals (Evans et al., 1993-1994). In a study of the subspecies Hapalemur griseus alaotrensis, Mutschler and Feistner (1995) found that the mean group size was 3.3 individuals. At Ranomafana National Park the average group size of the gray gentle lemur was found to be 4.5 individuals (Tan, 1999). The gray gentle lemur is a crepuscular species (Petter and Peyrieras, 1975; Santini-Palka, 1994); although Overdorff et al. (1997) found that this species tended to be more diurnal. This is an arboreal species. This species has been observed to move and feed early in the morning, with a long rest period during the midday and then later in the evening another period of foraging before retiring to sleep (Pollock, 1986; Petter and Peyrieras, 1975; Overdorff et al., 1997). Wright (1986) found that 48% of the time in a day was devoted to eating. In the Hapalemur griseus alaotrensis subspecies, group's home ranges were not found to overlap (Nievergelt et al., 1998a); members of a group will scent-mark on papyrus at the edge of territories (Nievergelt et al., 1998a). Group members will sleep during the night in close contact in emergent trees (Wright, 1986). The sleeping sites are located throughout the home range, with one tree being used each night and the same sleeping site is used several times in a month (Wright, 1986). Groups will enter sleeping sites between 15:45 and 17:25 in the late afternoon and evening (Wright, 1986).

When disturbed, this species will drop down to the ground and then freeze or move away quietly (Pollock, 1986). Predators of the gray gentle lemur include the ring-tailed mongoose Galidia elegans, the boa Sanzinia madagascariensis, Buteo brachypterus, Polybiroides radiatus, and humans Homo sapiens (Pollock, 1986). The large boid snake, Boa manditra, will also prey upon the gray gentle lemur (Rakotondravony et al., 1998). The fossa, Cryptoprocta ferox may be a predator of the gray gentle lemur (Wright et al., 1998).

LOCOMOTION:
The gray gentle lemur moves by leaping through the forest (Terranova, 1996). When this species lands it usually will land on its hindlimbs on an oblique support (Terranova, 1996). Landing on all four limbs is the second most common landing type and this tends to occur more on vertical supports than on oblique ones (Terranova, 1996). Landing on the forelimbs tends to be rare and these solely occur on oblique supports (Terranova, 1996). For long distance leaps, vertical supports are used more frequently where during shorter leaps oblique supports are used more (Terranova, 1996). For takeoffs, oblique supports are most commonly utilized (Terranova, 1996). The gray gentle lemur will also move through the forest quadrupedally (Petter and Peyrieras, 1975). The subspecies Hapalemur griseus alaotrensis has been known to swim, in a dog-like fashion, and even mothers with infants have been known to swim (Petter and Peyrieras, 1975).

SOCIAL BEHAVIOR:
The gray gentle lemur shows both monogamous and unimale social systems (Tan, 1999; Mutschler et al., 2000). This species either has a monogynous or polygynous mating system. Mating and social systems in this species is probably due to defense of resources rather than defense of females (Mutschler et al., 2000). Females in polygynous groups tend to have more offspring than females in monogamous groups (Mutschler et al., 2000). Solitaries were found to occur and tend to be female (Mutschler et al., 2000). Females disperse from their natal group while still a subadult, and males will remain in their natal group until adulthood then disperse (Mutschler et al., 2000). This is a territorial species (Nievergelt et al., 1998a). Agonistic interactions will often occur when two groups encounter each, but severe fighting and injuries almost never occur with the resident group driving out the intruding group (Nievergelt et al., 1998a). During these interactions behavioral patterns such as substrate marking, tail scent-marking, and vocalizations would transpire (Nievergelt et al., 1998a). Group encounters last from 7-124 minutes (Neivergelt et al., 1998b). Both sexes participate in group encounters with males playing a larger role (Neivergelt et al., 1998b). Males were found to penetrate into neighboring groups more than females (Neivergelt et al., 1998b).

VOCAL COMMUNICATION:
purring: This call is emitted by the infant and is heard when an individual is licked or stroked by its mother (Petter and Charles-Dominique, 1979). This call is comparable to one emitted by the infant Microcebus murinus (Petter and Charles-Dominique, 1979).

infant distress call: This is a high-pitched call that is emitted by infants upon separation from their mothers, but are still in visual contact of them (Petter and Charles-Dominique, 1979).

oeeeee: This call is uttered by the infant upon the return of its mother (Petter and Charles-Dominique, 1979).

hon: This is a short, grunt-like sound emitted by the adult female in response to the oeeeee vocalization (Petter and Charles-Dominique, 1979). This is also uttered by all members of the group during periods of active to maintain group cohesion (Petter and Charles-Dominique, 1979). This call may be variable in strength, rhythm, and pitch (Petter and Charles-Dominique, 1979). This call is also heard when two individuals engage in social groomin (Petter and Charles-Dominique, 1979).

coooee: This call is used when individuals are a long distance apart (Petter and Charles-Dominique, 1979). When uttering this call the sender usually will keep still and stare blankly ahead (Petter and Charles-Dominique, 1979). This is responded to with the same call or simple grunts (Petter and Charles-Dominique, 1979).

mating call: This call is emitted by both adult males and females and is heard during episodes of high sexual arousal (Petter and Charles-Dominique, 1979). This call starts out with a weak, high-pitched, trembling component that turns into a rapid sequence of low frequency, resonant sounds (Petter and Charles-Dominique, 1979).

mild alarm call: This call begins with weak, rapidly emitted grunts that transforms into a double-grunt that sounds like "co-dot" (Petter and Charles-Dominique, 1979). This call is uttered by all members of the group (Petter and Charles-Dominique, 1979). The intensity of the grunts varies according to the degree of the disturbance (Petter and Charles-Dominique, 1979). The call rou-fou may be heard with this call (Petter and Charles-Dominique, 1979).

rou-fou: This call is interspersed with mild alarm call during moderate levels of alarm (Petter and Charles-Dominique, 1979).

high-intensity alarm call: This call consists of powerful "co-dot" grunts followed by a "co-ouiiiiiii" sound (Petter and Charles-Dominique, 1979). This call is usually emitted in unison by group members (Petter and Charles-Dominique, 1979).

tooth-grinding: This occurs when an individual becomes aggressive and excited and is very audible sound (Petter and Charles-Dominique, 1979). An example of this occurring is when an infant is born and the mother does this to keep other group members away (Petter and Charles-Dominique, 1979).

intimidation call: This call sounds like "creee" and is emitted by an individual that feels seriously threatened (Petter and Charles-Dominique, 1979). This call serves to communicate aggression (Petter and Charles-Dominique, 1979).

high-pitched grunts: These sounds are emitted by adult males when they want to communicate aggression (Petter and Charles-Dominique, 1979). These sound like grunts uttered by Lemur catta (Petter and Charles-Dominique, 1979).

OLFACTORY COMMUNICATION:
substrate scent-marking: This is when a male Hapalemur griseus alaotrensis will first damage papyrus by scratching the lower first dentition, then rub the spot with their brachial gland (Neivergelt et al., 1998b). Females will also perform this behavior but will deposit urine with the anogenital region by sit-rubbing (Neivergelt et al., 1998b).

tail scent marking: This is when an individual will stand on the hind legs with the tail bent towards and between the legs, and rubs the tail with the inside of both wrists, beginning at the base and ending at the tip (Neivergelt et al., 1998b). This behavior is performed at the top of a papyrus plant and is done towards an opponent (Neivergelt et al., 1998b). Visual monitoring will often accompany this behavior (Neivergelt et al., 1998b).

scent marking of group members: This is when an individual will sit behind a conspecific and rub from the neck to the middle of the back with the insides of the wrists (Neivergelt et al., 1998b). The performer of this behavior may sit face-to-face with the receiver of this behavior (Neivergelt et al., 1998b). During this behavioral pattern self-grooming or social grooming may occur (Neivergelt et al., 1998b). Before and after this behavior substrate scent-marking occurs by the performer (Neivergelt et al., 1998b).

VISUAL COMMUNICATION:
visual monitoring: This is when one individual of a group will stare at an individual of another group and/or another group (Neivergelt et al., 1998b). This behavior is often accompanied by a rapid to- and fro- movement of the tail (Neivergelt et al., 1998b). This behavior lasts from 1-5 minutes and the performer is usually 3-30 meters from the receiver(s) (Neivergelt et al., 1998b).

display locomotion: This is when an individual will run very quickly in circles at the border of vegetation (Neivergelt et al., 1998b).

chase away: This is when an individual will rapidly and closely follow a conspecific and pursue it until it leaves the area (Neivergelt et al., 1998b). Before this behavior visual monitoring will occur (Neivergelt et al., 1998b).

confrontation display: This is when an individual will run at an intruding conspecific and stop in front of it without touching (Neivergelt et al., 1998b). The receiver of this behavioral pattern will jump back then perform the behavior reciprocally (Neivergelt et al., 1998b). This behavior is performed back-and-forth many times with substrate scent-marking, tail scent marking, and visual monitoring occurring during bouts (Neivergelt et al., 1998b).

TACTILE COMMUNICATION:
social grooming: This is when one individual removes dead skin and parasites from another conspecific. Infants are groomed by others more for the first six months of their lives than they groom others themselves (Steyn and Feistner, 1994).

REPRODUCTION:
In the wild, the gray gentle lemur gives birth to a single offspring, but twins have known to occur for the subspecies Hapalemur griseus alaotrensis (Taylor and Feistner, 1998; Mutschler et al., 2000). In captivity twins have known to occur, and it was found that twins place placed an extra energentic burden on the mother in terms of carrying and suckling as compared to singletons (Taylor and Feistner, 1998, 1996). Pollock (1986) found that the birth season for the gray gentle lemur starts in late October and extends to January. However Petter and Peyrieras (1975) found that the birth season for this species at the Maroantsetra region is from January to February. The birth season for the subspecies Hapalemur griseus alaotrensis was found to range from September to February (Mutschler et al., 2000). The gestation period for this species is 140 days (Pollock, 1986).

Infants are born with open eyes and the pelage is similar to that of the adults' (Steyn and Feistner, 1994). Infants will only consume mother's milk for the first six weeks, although they will "mouth" objects from day six (Steyn and Feistner, 1994). The mother at first will hold the infant while suckling milk, but as the infant gets older and larger, the infant will adopt a sitting posture (Steyn and Feistner, 1994). Starting at week six, the infants will begin to eat little pieces of bamboo, though they are still dependant upon the mother for milk (Steyn and Feistner, 1994). At about week twenty, the infant is weaned from its mother (Steyn and Feistner, 1994). Infants will begin to move on their own by day six, and by week three the infant is able to jump, hop, and walk on substrates (Steyn and Feistner, 1994). Young are reported to be carried in the mouth by their mothers, and only dorsally in the wild and both ventrally and dorsally in captivity (Klopfer and Boskoff, 1979; Petter and Peyrieras, 1975). At about the fourth week of age the infant begins to groom itself regularly (Steyn and Feistner, 1994).

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Last Updated: March 15, 2007.
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