Slow Loris (Nycticebus coucang)

Slow Loris (Nycticebus coucang)

MORPHOLOGY:
This species has dark rings around the eyes and a white nose, which make it stand out. These primates have a special reticulum in their hands and feet which remove lactic acid build up allowing them to grasp with their hands and feet for hours. The thumb and the big toe are perpendicular to the other digits (Nowak, 1999). In females the vulva is closed until estrus. The saliva of this species is toxic and is used in defense against predators (Alterman, 1995). Mothers will spread the toxin on their infants with the use of the toothcomb (Alterman, 1995). The nail on the second digit of each foot is shaped more like a claw and is used in grooming. The toilet claw is usually licked right after grooming (Tenaza et al., 1969). A brown ring circles the eyes of the slow loris (Choudhury, 1992). The pelage of the face is pale brown to whitish in color with dark markings (Choudhury, 1992). The head and the shoulders may have a color that is gray, creamy or dull silvery white (Choudhury, 1992). The dorsal side is reddish brown to gray in color (Choudhury, 1992). The flanks and rump of this species are either buff, rusty, or ashy-gray (Choudhury, 1992). There is a brown dorsal stripe that extends from the crown down to the back (Choudhury, 1992). The average body mass for an adult male slow loris is around 670 grams and for the female it is around 626 grams (Barrett, 1984). Females have two pairs of mammae, one pectoral and one in the lower thoracic area (Izard et al., 1988).

RANGE:
This species is found in the following countries: Bangladesh, Brunei, Burma, Cambodia, India, Indonesia, Laos, Malaysia, Thailand, and Vietnam. In India the slow loris is found in the states of Assam, Arunachal Pradesh, Nagaland, Manipur, Mizoram, Tripura, and Meghalaya (Choudhury, 1992). In the Philippines this species is found on the islands of Simunul, Bongao, Sanga Sanga, and Tawitawi, where Tawitawi represents this species most eastern most limit (Fooden, 1991). It lives in the main canopy of the forest. The slow loris prefers the edge habitat of the forest, possibly because the edge has more supports that may increase foraging efficiency (Johns, 1986). In India this species is found in tropical evergreen, semi-evergreen, tropical mixed deciduous, and sub-tropical broadleaf type forests (Choudhury, 1992).

ECOLOGY:
This species is a frugivorous species, but will also eat insects, leaves, and bird's eggs. The slow loris will forage for arthropods in the lower story of the canopy and in the thick tangles of lianas and climbers, or tangled logging debris (Johns, 1986). This species consumes some invertebrate prey that has a repugnant smell and taste, much the slender loris, Loris tardigradus (Hladik, 1979). In Malaysia, this species was observed to feed upon a common giant snail, Achatina fulica (Elliot and Elliot, 1967). Gums are also consumed by this species (Johns, 1986). This species drinks liquids bending down towards the source and lapping up the liquid (Tenaza et al., 1969). The slow loris will sleep in a sitting position or lying on the back, side or belly (Tenaza et al., 1969). When sleeping in a sitting position the head is often turned away from the midline (Tenaza et al., 1969). It also been reported to sleep in a ball with its head between its thighs (Choudhury, 1992). This species will stretch out when sleeping when the weather is hot (Tenaza et al., 1969). During the day the preferred sleeping sites are holes and crevices among trees or in dense bamboo clumps (Choudhury, 1992). The slow loris is a nocturnal and almost entirely arboreal species (Choudhury, 1992).

LOCOMOTION:
This species moves slowly and quadrupedally through the trees. The slow loris can move both above and below the branches (Ehrlich and Musicant, 1977). This species can hang below a branch by one or both feet for long periods of time (Ehrlich and Musicant, 1977). When moving this species always has at least three extremities (hands or feet) grasping a support (Walker, 1979). Also when moving the fore and hind foot of the same side are brought together before the grip is transferred (Walker, 1979). The slow moving behavior of this species is only relatively slow, and this species is capable of moving as fast other prosimians like members of the genus Galago (Ehrlich, 1969).

SOCIAL BEHAVIOR:
Males have home ranges that overlap those of a number of females, checking the urine marks to see if a female is in estrus. Agonistic encounters between conspecifics rarely result in serious attacks, rather mostly threats occur (Ehrlich and Musicant, 1977). Males are highly territorial and will not allow another male in their territory (Nowak, 1999). When foraging mothers will park their infants even when they are only a couple of weeks old (Ehrlich and MacBride, 1989). Infants most often cling to their mother's ventrum even when she is locomoting (Ehrlich and MacBride, 1989). Infants start to become more active after the first 6-8 weeks, and after 16 weeks infants are primary individuals that initiate social contact with the mothers (Ehrlich and MacBride, 1989). In captivity mothers will protect the infants from other group members (Ehrlich and MacBride, 1989). Slow loris infants develop at a comparatively slow rate as compared with other nocturnal prosimians (Ehrlich and MacBride, 1989).

Social play exists in this species with play-fighting as an exhibit of this behavior (Ehrlich and Musicant, 1977). During play-fighting both participants would be hanging by one or two feet with one sometimes supporting the weight of the two (Ehrlich and Musicant, 1977). Arms and legs can be twined during play-fighting (Ehrlich and Musicant, 1977). The slow loris will solicit play with the behavioral patterns head-butt and body wriggle (Ehrlich and Musicant, 1977). Play-fighting that lasts for an extended period of time will sometimes be broken up with rest periods (Ehrlich and Musicant, 1977).

VOCAL COMMUNICATION:
long-distance whistle: This call has a duration of 150-260 milliseconds (Zimmermann, 1985). The fundamental frequency range of this call is from 4.5-7.4 kilohertz (Zimmermann, 1985). This call may given singly or at an irregular rate and the intensity is medium to high (Zimmermann, 1985). This call is emitted by both males and females (Zimmermann, 1985). This call is heard in different situations including: spontaneously, during foraging, urine marking of objects, passing by individuals or observing surroundings or individuals (Zimmermann, 1985). This call serves to communicate separation and is responded to with the same call (Zimmermann, 1985). Mothers will use this call as a response to infants when they are calling and are separated (Zimmermann, 1985).

mating whistle: This is an up- and downward frequency modulated sound that has a sound intensity of low to medium (Zimmermann, 1985). The fundamental frequency range of this call is from 2.1-4.67 kilohertz (Zimmermann, 1985). The duration of this call is 120-240 milliseconds, and this call may be emitted singly or at an irregular rate (Zimmermann, 1985). A female utters this call during the time of estrus (Zimmermann, 1985). This call is uttered upon visual contact with the male (Zimmermann, 1985). This call serves to solicit copulation on the part of the estrus female (Zimmermann, 1985).

copulation whistle: This is a down- and upward modulated sound with a sound intensity that is low (Zimmermann, 1985). The fundamental frequency range of this call is from 1.1-2.4 kilohertz (Zimmermann, 1985). The duration of this call is 110-240 milliseconds and it is emitted at an irregular rate (Zimmermann, 1985). This call is heard during sexual interactions of close proximity between males and females (Zimmermann, 1985). During copulation both the male and the female will emit this call when hanging upside-down from a branch (Zimmermann, 1985). The female will also give this call when being mounted by the male (Zimmermann, 1985).

short kecker: This call is short, has a broadband (0.533-13.5 kilohertz), and has a sound intensity that is low to medium (Zimmermann, 1985). The duration of this call is 20-100 milliseconds and may be emitted in sequences of up to six calls (Zimmermann, 1985). The inter-call interval for this call is between 25-120 milliseconds (Zimmermann, 1985). This call is emitted by both males and females (Zimmermann, 1985). This call is heard in situations of social play and serves to focus attention of group members on to the individual that is emitting the call (Zimmermann, 1985).

long kecker: This is a short, broadband call that has a duration of 5-50 milliseconds (Zimmermann, 1985). This call is emitted in a series of 63 calls (Zimmermann, 1985). The frequency range of this call is from 0.40-0.88 kilohertz (Zimmermann, 1985). The inter-call interval is from 35-450 milliseconds (Zimmermann, 1985). This call is uttered by both males and females (Zimmermann, 1985). This call is heard during mild aggression between familiar conspecifics (Zimmermann, 1985). This call may also be heard when an individual defends its food against other group members (Zimmermann, 1985). This call serves to communicate mild threat (Zimmermann, 1985). The receiver of this call often retreats (Zimmermann, 1985).

scream: This call is described as a slight upward frequency modulated sound with a sound intensity of medium to high (Zimmermann, 1985). The frequency range for this call is from 0.53 to 1.6 kilohertz (Zimmermann, 1985). The duration of this call is from 160-1100 milliseconds (Zimmermann, 1985). This call is uttered by both males and females (Zimmermann, 1985). This call is heard during agonistic interactions; during fight the submissive individual will emit this when seized by the aggressor (Zimmermann, 1985). The emission of the call allows the submissive individual to be able to retreat (Zimmermann, 1985). This call communicates submission (Zimmermann, 1985).

snarl: This call is a short broadband noisy sound with a sound intensity of low to medium (Zimmermann, 1985). The frequency range for this call is from 0.133-16 kilohertz (Zimmermann, 1985). The duration of this call is 20-250 milliseconds and the call may be emitted in sequences of 16 calls (Zimmermann, 1985). The inter-call interval is from 60-140 milliseconds (Zimmermann, 1985). This call is heard upon the approach of potential predators or unpleasant or unfamiliar conspecifics (Zimmermann, 1985). This call serves to communicate threat (Zimmermann, 1985).

grunt: This call is a narrow-band noisy sound that is emitted by both males and females (Zimmermann, 1985). The frequency range for this call is from 0.66-3.2 kilohertz (Zimmermann, 1985). The inter-call interval is from 100-1900 milliseconds (Zimmermann, 1985). This call is heard in conjunction with snarl from a female not in estrus threatening a male wishes to copulate with the female (Zimmermann, 1985). This call serves to communicate threat (Zimmermann, 1985). This call is heard upon the approach of potential predators or unpleasant or unfamiliar conspecifics (Zimmermann, 1985).

click: This call is a series of discreet, rapid clicks and squeaks (Daschbach et al., 1981). This call is uttered by infants when they are disturbed (Daschbach et al., 1981). The duration of this call is 0.04 seconds (Daschbach et al., 1981).

OLFACTORY COMMUNICATION:
This is very important for this species. The slow loris tells conspecifics apart by the scent markings. They have glands on the face, chest, arms, and palms. They also communicate physical state and position by olfactory communication.

perineal rubbing: This is when an individual will rub their perineal region upon the substrate, most often the ground or floor (Tenaza et al., 1969). Individuals will sometimes deposit urine when performing this behavior (Tenaza et al., 1969). This behavior serves as a marking behavior (Tenaza et al., 1969).

VISUAL COMMUNICATION:
solicit grooming: This is when an individual that wishes to be groomed will present that part of the body in which grooming is desired to another individual (Ehrlich and Musicant, 1977).

body wriggle: This is when an individual will hang by the feet and wriggle the body with the arms clasped over the head (Ehrlich and Musicant, 1977). This behavior serves to communicate the desire to engage in social play (Ehrlich and Musicant, 1977).

TACTILE COMMUNICATION:
attack: This is when a slow loris will bite, lunge-bite, push, pull, or strike with the hands another individual (Ehrlich and Musicant, 1977). A lunge-bite is when the body is held in place while the head and neck are thrust at the opponent (Ehrlich and Musicant, 1977). This behavior is used to communicate aggression (Ehrlich and Musicant, 1977).

fight: This is when two individuals will attack each other mutually (Ehrlich and Musicant, 1977).

social grooming: This is when one individual will groom another removing dead skin and parasites. During this behavior the groomer will hold the groomee with one hand and sometimes tilt the head with the hand of the individual being groomed (Ehrlich and Musicant, 1977). This behavior can occur with one or more of the participants hanging by the feet (Ehrlich and Musicant, 1977). The parts of body that received the most attention are as follows: trunk (48%); face, head, neck (28%); extremities (19%); and anogenital area (5%) (Ehrlich and Musicant, 1977).

head-butt: This is when one individual will butt with the head or another body part another individual (Ehrlich and Musicant, 1977). This behavior serves to communicate the desire to engage in social play (Ehrlich and Musicant, 1977).

REPRODUCTION:
This species gives birth to a single offspring with twins occurring rarely (Izard et al., 1988). Females reach puberty between the ages of 18 and 24 months, with males reaching puberty slightly earlier (Izard et al., 1988). During estrus the genitalia of the female becomes swollen and pink (Izard et al., 1988). The female will signal that she is receptive to copulations by the male by suspending the body upside down (Doyle, 1974). Copulations occur with the female hanging upside-down from a support (Izard et al., 1988). Sometimes after a copulation bout the male leave a copulatory plug (Izard et al., 1988). The slow loris has a gestation length that ranges from 185-197 days (Izard et al., 1988). Izard et al. (1988) found that the average interbirth interval for this species is 16.2 months. It was found that in captivity that most of the births occurred between March and May (Izard et al., 1988). Although other authors report that this species does not have any birth season (Van Horn and Eaton, 1979).

REFERENCES:
Alterman, L. 1995. Toxins and toothcombs: Potential allospecific chemical defenses in Nycticebus and Perodicticus. in Creatures of the Dark: The Nocturnal Prosimians. eds. L. Alterman, G.A. Doyle, and M.K. Izard. Plenum Press: New York.

Barrett, E. 1984. The Ecology of Some Nocturnal, Arboreal Mammals in the Rainforest of Peninsular Malaysia. Ph.D. dissertation, Cambridge University.

Burton, F. 1995.The Multimedia Guide to the Non-human Primates. Prentice-Hall Canada Inc.

Choudhury, A.U. 1992. The slow loris (Nycticebus coucang) in North-east India. Primate Report. Vol. 34, 77-83.

Daschbach, N.J., Schein, M.W., and Haines, D.E. 1981. Vocalizations of the slow loris, Nycticebus coucang (Primates, Lorisidae). International Journal of Primatology. Vol. 2(1), 71-80.

Doyle, G.A. 1974. Behavior of Prosimians. in Behavior of Nonhuman Primates, Vol. 4. eds. A.M. Schrier and F. Stollnitz. Academic Press.

Ehrlich, A. 1969. Behavioral characteristics of the slow loris, galago, and rhesus monkey. Recent Advance in Primatology. Vol. 1, 119-127.

Ehrlich, A. and MacBride, L. 1989. Mother-infant interactions in captive slow lorises (Nycticebus coucang). American Journal of Primatology. Vol. 19, 217-228.

Ehrlich, A. and Musicant, A. 1977. Social and individual behaviors in captive slow lorises. Behaviour. Vol. 60, 197-219.

Elliot, O. and Elliot, M. 1967. Field notes on the slow loris in Malaya. Journal of Mammalogy. Vol. 48(3), 497-498.

Fooden, J. 1991. Eastern limit of distribution of the slow loris, Nycticebus coucang. International Journal of Primatology. Vol. 12(3), 287-290.

Hladik, C.M. 1979. Diet and ecology of prosimians. in The Study of Prosimian Behavior. eds. G.A. Doyle and R.D. Martin. Academic Press: New York.

Izard, M.K., Weisenseel, K.A., and Ange, R.L. 1988. Reproduction in the slow loris (Nycticebus coucang). American Journal of Primatology. Vol. 16, 331-339.

Johns, A.D. 1986. Effects of selective logging on the behavioral ecology of West Malaysian primates. Ecology. Vol. 67(3), 684-694.

Nowak, R.M. 1999. Walker's Primates of the World. The Johns Hopkins University Press: Baltimore.

Tenaza, R., Ross, B.A., Tanticharoenyos, P., and Berkson, G. 1969. Individual behaviour and activity rhythms of captive slow lorises (Nycticebus coucang). Animal Behaviour. Vol. 17, 664-669.

Van Horn, R.N. and Eaton, G.G. 1979. Reproductive physiology and behavior in prosimians. in The Study of Prosimian Behavior. eds. G.A. Doyle and R.D. Martin. Academic Press: New York.

Walker, A. 1979. Prosimian locomotor behavior. in The Study of Prosimian Behavior. eds. G.A. Doyle and R.D. Martin. Academic Press: New York.

Zimmermann, E. 1985. Vocalizations and associated behaviours in adult slow loris (Nycticebus coucang). Folia Primatologica. Vol. 44, 52-64.

Last Updated: March 24, 2007.
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