This species has a sacculated stomach to assist in the breakdown of cellulose. Phayre's
leaf-monkey has enlarged salivary glands to assist it in breaking down food. The dental formula of Phayre's leaf-monkey is
2:1:2:3 on both the upper and lower jaws (Ankel-Simons, 2000). Males have larger
canines than females (Pan et al., 1993). The length of the head and body range
from 44-61 centimeters and tail length for this species ranges from 65-86 centimeters
(Choudhury, 1987). The average body mass of an adult male Phayre's leaf-monkey is
around 7.3 kilograms, and for the female it is around 6.2 kilograms (Fleagle, 1988). The
pelage color for Phayre's leaf-monkey is dark ashy-bluish brown on the dorsal side and
whitish on the ventral side (Choudhury, 1987). The head and tail ends of this species are
darker than the rest of the body (Choudhury, 1987). Srivastava (1999) describes the upper
arms, legs, and tail as being silvery gray in coloration. The lips and the area around each
of the eyes are whitish (Choudhury, 1987). Infants are straw colored (Roonwal and
Mohnot, 1977). Srivastava (1999) describes the infants as being orange in color that
begins to change after 3 months of age. This species has an extended cap of hair on the
head that occurs in all individual except newborn infants (Srivastava, 1999).
This species has three subspecies each having differing pelage colorations:
- Trachypithecus phayrei phayrei: The dorsal side either dark brown, buffy, or
gray-brown and the ventral side is gray or whitish in coloration (Groves, 2001). Around
the eye there is a white ring (Groves, 2001).
- Trachypithecus phayrei crepusculus: This subspecies has a body coloration
of gray to gray-fawn or silvery brown to nearly yellow (Groves, 2001). This subspecies
has a forehead that is brown becoming lighter over the crown, being creamy sometimes
on the nape (Groves, 2001). The hands and feet are black (Groves, 2001). Has white eye-
rings and a small are of depigmentation around the mouth (Groves, 2001).
- Trachypithecus phayrei shanicus: The overall color of this subspecies is
described as fawn, with a trace of lightening on the nape (Groves, 2001). Hands and feet
are slightly darker than the rest of the body (Groves, 2001). Around the eyes the white is
restricted to the inner side and the depigmented area around the mouth is wide (Groves,
2001). A whorl is found behind the brows, but there is no crest on the crown (Groves,
Phayre's leaf-monkey is found in the countries of Bangladesh, Burma, China, India,
Thailand, and Vietnam (Srivastava, 1999; Roonwal and Mohnot, 1977; Gupta and
Kumar, 1994; Stanford, 1988; Ruggeri and Timmins, 1995/1996). In India, this species is
found in Tripura, Mizoram, and Assam (Choudhury, 1987, 1994; Mukherjee, 1982;
Srivastava, 1999). In Assam, Phayre's leaf-monkey is found in the districts of Cachar,
Hailakandi, and Karimganj (Choudhury, 1996). This species is found in Huai Kha
Khaeng Reserve, Thailand and in Pidaung and Pegu Yoma Reserves in Burma
(MacKinnon and MacKinnon, 1987). This species lives in primary and secondary forests, and also on tea
estates where bamboo thickets are found (Wolfheim, 1983; cited in Nisbett and Ciochon,
1993). In Assam Phayre's leaf-monkey was found to live in depleted evergreen forests
containing bamboo, favoring habitats dominated by the shrub Macaranga
denticulata and the herb Alpinia allughas (Choudhury, 1987, 1994, 1996). In
Mizoram this species was found in secondary forests and a dense bamboo forest with a
few scattered trees (Raman et al., 1995). In Bangladesh this species lives in semi-
evergreen forests and semi-deciduous/evergreen forests (Feeroz et al., 1995;
Gittins and Akonda, 1982). In Vietnam, this species is found in the localities of: Phu
Quy, Muong Cha, Phu Yen, Lang Chanh, Quan Hoa, Nghia Dung, and Quy Chau
(Nisbett and Ciochon, 1993; Wolfheim, 1983). Ratajszczak (1988) reports that this
species is found in Cuc Phuong National Park in Vietnam. In Burma, this species lives in
dense high forests and in bamboo forests along hillsides and along the banks of streams
(Roonwal and Mohnot, 1977). In Thailand, Phayre's leaf-monkey lives in evergreen
forests, 15-50 meters above the ground (Roonwal and Mohnot, 1977). Phayre's leaf-
monkey is found in higher densities in mixed-species plantations than in monoculture
plantations (Gupta, 1997).
This species has three subspecies each having a differing range:
- Trachypithecus phayrei phayrei: This subspecies is found from Pegu north
through Arakan to Tripura and southern Assam, India and in eastern Bangladesh (Groves,
- Trachypithecus phayrei crepusculus: This subspecies is found in Bangladesh,
southern China, southwestern Laos, central and northwestern Thailand, and northern
Vietnam (Groves, 2001). In Bangladesh this subspecies occurs to the south of the range
of the subspecies Trachypithecus phayrei phayrei (Groves, 2001).
- Trachypithecus phayrei shanicus: This subspecies is found from northern
Burma into southern Yunnan, China in the Yingjiang-Namting River and Tunchong-
Homushu Pass Districts (Groves, 2001).
Phayre's leaf-monkey is a folivorous species
(Ahsan, 1994; Roonwal and Mohnot, 1977; Gupta and Kumar, 1994; Stanford, 1988;
Choudhury, 1994; Gupta, 1996; Bose and Bhattacharjee, 2002). This species prefers to
consume immature leaves to more mature ones (Bose and Bhattacharjee, 2002). In the
Inner Line Reserve Forest of Assam, this species was found to mainly consume bamboo
shoots (Srivastava, 1999). In southern Assam the three most preferred food items were
Teinestachum dulloea, Dendrocalamus griffithii, and Mokania
micrantha (Bose and Bhattacharjee, 2002). At Sipahijala, Tripura, young rubber
shoots are an important part of the diet during the dry season (Srivastava, 1999). Gupta
(1997) found that 38% of the total time feeding was spent on feeding on plantation
species. An exotic plantation species, Akashmani (Acacia auriculiformis),
accounted for 18.3% of the time feeding on plantation species (Gupta, 1997). There are
two feeding peaks for this species, one in the early morning and one in the late afternoon
(Srivastava, 1999). Phayre's leaf-monkey will sometimes break-up into subgroups when
foraging (Srivastava, 1999; Choudhury, 1994). Groups will spread out far when foraging
(Ahsan, 1994). More time is devoted to feeding during the winter months (36.9%) than in
summer (33.6%) or the monsoon (31.1%) months (Gupta and Kumar, 1994).
Gupta and Kumar (1994) found that in Gumti Wildlife Sanctuary, Tripura, India, the diet
consists of young and mature leaves, ripe and unripe fruits, seeds, petioles, flowers, and
gums. Gupta and Kumar (1994) over an eight month study found that young leaves
consisted of 48.5% of the diet, followed by the young pods and seeds of two leguminous
species (Albizzia procera and Albizzia lebbek), unripe and partly ripe
fruit of two Ficus species accounted for 5.2% of the diet, and the last 20.6% of
the diet consisted of petioles, gums, and flowers. Young leaves were consumed most in
June (81.7%) and least in March (22.0%) (Gupta and Kumar, 1994). Seeds were found to
be more in the months of January, February, and March when eating young leaves was
low (Gupta and Kumar, 1994). Feeding on mature leaves was low, only consisting of
feeding on the leaves of the bamboo species Melocanna bambusoides (Gupta and
Kumar, 1994). Gupta and Kumar (1994) found that the feeding on young leaves
depended on their abundance and not their availability. The most important food sources
at Gumti Wildlife Sanctuary were Albizzia procera, Melocanna
bambusoides, Callicarpa arborea, and Albizzia stipulata, Albizzia
lebbek (Gupta and Kumar, 1994). Albizzia procera was used the most with
its young leaves, pods and seeds, and gum being utilized (Gupta and Kumar,
Group sizes range from 3 to 30 individuals. In
Yunnan, China, group sizes for this species were found to range from 30-40 individuals
(Zhen, 1991; cited in Pan et al., 1993). He and Yang (1982; cited in Pan et
al., 1993) found that group sizes ranged from 4-8 individuals. In Bangladesh, the
mean group size was found to be 11 individuals (Ahsan, 1994). In Rajkandi Reserve
Forest, Bangladesh, group sizes were found to average 8.8 individuals (Stanford, 1988).
This is an arboreal and a diurnal species, although it will move around the
ground occasionally to move or to feed (Choudhury, 1994). Groups have a relatively
small home range size due to a high
percentage of folivory (Gupta, 2002). Daily activity consists of feeding (34.9%), resting
(21.15), traveling (14.4%), and other (29.5%, playing, grooming, etc.) (Gupta and
Kumar, 1994). More time is spent feeding and less time resting during the winter months
(Gupta and Kumar, 1994). Gupta (1997) found that in another study (12 months), in
Tripura, India, daily activity consisted of 41.7% feeding, 28.3% resting, 8.2% traveling,
and 21.8% other activities (grooming, calling, playing, suckling, aunting, etc.). Bose and
Bhattacharjee (2002) found that in southern Assam, group daily activity consisted of
39.4% feeding, 14.8% moving (traveling), 34.4% resting, 7.2% grooming, 1% playing,
and 3.2% other activities. Groups will awake shortly before dawn, feed, then find a place
to rest (Choudhury, 1994). In the late afternoon, groups will feed again (Choudhury,
1994). During the winter months, individuals will bask in the sun like capped langurs
(Choudhury, 1994). Sleeping sites range in height from 8 to 29 meters (Gupta,
Phayre's leaf-monkey moves through the forest quadrupedally (Fleagle,
Phayre's leaf-monkey has either a unimale or a multimale-multifemale social system; in
the multimale-multifemale usually there are two males (Gupta and Kumar, 1994;
Choudhury, 1994). The number of females in a group will range from 3 to 6 (Gupta and
Kumar, 1994). Solitary individuals have been reported for this species (Srivastava, 1999).
This is a territorial species and will defend its territory against conspecific groups. When a group is alarmed,
the females will grab their infants and run throughout the forest, leaping from tree to tree
while a male stays behind to watch and bark at the intruder (Roonwal and Mohnot, 1977).
Infants will be transferred between females (Srivastava, 1999). Gupta (2000) observed a
group's reaction to a dead member of the group and found that they remained close to the
body, touching and caressing it. Gupta (2000) also found that a neighboring group also
came near the body, but there was no aggression between the groups, which is usually
expected. Neighboring groups may be related and the second group may have protected
the first group from predators because the dead body was on the ground and Phayre's
leaf-monkey rarely descends to the ground (Gupta, 2000). Remaining close to the body
may reduce the stress of the group members (Gupta, 2000).
In the West Bhanugach Reserve Forest of Sylhet, Bangladesh, Phayre's leaf-monkey is
sympatric with the capped langur, Trachypithecus pileatus (Feeroz et
al., 1995). This species is also sympatric with the capped langur in Rajkandi Reserve
Forest where they will feed in the same or adjacent trees (Stanford, 1988).
Humans, Homo sapiens, predate upon Phayre's leaf-monkey (Roonwal and
Mohnot, 1977). Leopards, Panthera pardus, is a potential predator of this species
loud call: This call is described as being a high pitched roar (Stanford,
whoo call: This is a soft warning call emitted by the adult male upon detection of
a predator (Srivastava, 1999).
cheng-kong call: This is a two-phased honking call emitted by the adult male to
bring the group together (Srivastava, 1999).
social grooming: This is when one
individual grooms another and is used to reinforce the bonds between
Phayre's leaf-monkey gives birth to a single offspring. Females will experience 3.57
menstrual cycles to conception (Lu et al., 2010). Average gestation length for this
species was found to be 205.3 days (Lu et al., 2010).
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Last Updated: January 11, 2011.
[Primate Fact Sheets]