Greater Galago (Otolemur crassicaudatus)


MORPHOLOGY:
The average body mass for the greater galago is around 1.2 kilograms for females and 1.4 kilograms for males. The dental formula of this species 2:1:3:3 on both the upper and lower jaw (Ankel-Simons, 2000). The greater galago has a reflecting tapetum, all-rod retina, and an elongated fundus to assist in seeing during the night (Randolph, 1971). This species has a philtrum and a rhinarium (Ankel-Simons, 2000). This species has large apocrine glands located on the scrotal and circum-labial skin, lips, and the muzzle (Clark, 1978). The penis of the male is 20 millimeters in length on average and swells in length at the tip (Anderson, 1998). The penis is also covered in spines that decrease in size towards the tip, and at the tip the end of the baculum is seen (Anderson, 1998, 2000). The spines of the penis are either uni- or bidentate (pointed) (Dixson, 1989).

This species has two subspecies each having distinct pelage colorations:

RANGE:
This species is found in Eastern and central Western Africa. In Malawi, this species is found in Lengwe National Park (Happold and Happold, 1992). The greater galago mainly lives in coastal forests and in riparian bush environments (Crompton, 1983). In the Makapan Valley in South Africa, this species was found to live in closed woodland systems and riverine habitats (Constantino, 2001). This species may also live in areas of plantation timber such as blue gum, black wattle or pine, where they are found next to natural forests (Bearder and Doyle, 1974). The greater galago is found in elevations between sea level and 1800 meters (Bearder and Doyle, 1974).

This species has two subspecies each having differing ranges:

ECOLOGY:
The main diet of the greater galago is gums and/or fruit; it also eats seeds, nectar, millipedes, and insects (Hladik, 1979; Clark, 1985). The species Acacia karroo is an important species consumed for gum by the greater galago (Clark, 1985). This species feeds on flowers from the baobab, Adansonia digitata, consuming mainly the sepals of the flowers (Coe and Isaac, 1965). In the Transvaal this species was found to feed on hard-shelled and woody, dried fruits (Masters et al., 1988). Seeds from the genus Grewia, flowers from the genus Combretum, and berries of Zizyphus mucronata have been found to be consumed in South Africa (Harcourt, 1986; Crompton, 1984). In Malawi, this species was found to forage for termites, Macrotermes sp. (Happold and Happold, 1992). Millipedes (Diplopoda) have been found to be consumed during the summer months in South Africa (Harcourt, 1986). The greater galago has been observed feeding on arthropods from the orders: Coleoptera, Orthoptera, Hymenoptera, Odonata, Chilopoda, and Isoptera in South Africa (Harcourt, 1986). They have not been observed in the wild to eat other vertebrates (Hladik, 1979). In captivity when a water basin filled with fish was placed before a greater galago, they fished the fish out and ate them (Welker, 1976). During the cold months of winter gum from the Acacia plants will constitute a greater part of the diet for this species (Nash and Weisenseel, 2000; Hladik, 1979; Harcourt, 1986). In South Africa, this species will spend 40 seconds gum feeding each night in the summer and 2280 seconds each night gum feeding in the winter (Harcourt, 1986). During the summer in South Africa the greater galago will feed on gum from all tree heights, but in the winter this species will only feed on gum from a height of about 25 feet (Harcourt, 1986). This species forages alone moving from food tree to food tree foraging on gum or capturing insects on flowering acacias (Clark, 1985). When foraging for termites this species will only use the lips and tongue while walking (Happold and Happold, 1992).

This species exists sympatrically with Galago moholi, and they can exist together because of niche partitioning in terms of food and habitat utilized (Constantino, 2001). The greater galago is a nocturnal and an arboreal species (Randolph, 1971). Light was found to reset the circadian cycle in this species, moving individuals into the inactive phase (Randolph, 1971). Individuals will follow the same pathways when foraging in the home range (Bearder and Doyle, 1974). This species was found to spend 19.3% of its time foraging and 49.0% of its time traveling (Crompton, 1983). The most common sleeping site for the greater galago is concealed in a dense tangle of creepers and branches at a height ranging from 5 to 12 meters above the ground (Bearder and Doyle, 1974). Greater galagos will select trees that have a dense growth of climbers such as Dalbergia armata and Pteralobium sp. (Bearder and Doyle, 1974). This species will rarely sleep on an exposed branch (Bearder and Doyle, 1974). Adult females will make nests when they have young infants, and these consist of leafy platforms that are inaccessible and depressed in the middle with foliage above to provide shelter (Bearder and Doyle, 1974). An individual has more than one sleeping site in their home range (Bearder and Doyle, 1974). Individuals will not move away from their sleeping site during the day (Bearder and Doyle, 1974). Juveniles may sleep with adult males as they become more independent (Clark, 1978). When autogrooming individuals will lick the hands, wrists, and lower forearms and these areas over the ears and eyebrows (Pinto et al., 1974). Also when autogrooming individuals will clean the insides of the ears with the fingers then lick the fingers when done (Pinto et al., 1974).

The chimpanzee, Pan troglodytes, has been found to be a predator of the greater galago (Uehara, 1997). Other predators of the greater galago include leopards, eagle owls, snakes, genets (Crompton, 1984).

LOCOMOTION:
This species, unlike other galagines, moves quadrupedally through the forest and bush. The greater galago can jump if it has to, but it does it in an awkward manner; it does it with relatively little force. When jumping this species uses its hind legs as a propulsive force (Bearder and Doyle, 1974). Shorter jumps are more common in this species with longer jumps being made occasionally and they are in a downward direction without much propulsion (Bearder and Doyle, 1974). When moving between supports Crompton (1983, 1984) describes a pattern called foliage cross, where an individual will pull the terminal supports towards the body to transfer between supports (e.g. tree branches). When moving on the ground this species moves by a "kangaroo-like" gait where only the hindlimbs are used, a "galloping" gait where both the fore and hind feet are used, and a walk or run where the hindquarters and tail are in the air (Bearder and Doyle, 1974). The types of supports used by this species were found to be sloping in nature (Crompton, 1983, 1984). Supports used by the greater galago also are larger compared to those by other galago species (Crompton, 1983, 1984). Infants start walking before climbing, walking at about 8 days (Ehrlich, 1974; Crompton, 1983). In a captive study, jumping was found to occur in infant greater galagos at the age of 31 days (Ehrlich, 1974). Infants were found to utilize the undergrowth more frequently than adults when traveling and twigs are used more often (Crompton, 1983). Infant support use also tends to more high-angled as compared to support use by adults (Crompton, 1983). Dietary needs in relation body size might influence why infants spend more time at heights below adults (Crompton, 1983).

SOCIAL BEHAVIOR:
This is a nocturnal species, with both sexes dispersing from the birth territory, however the males may return avoiding the resident dominant male. Males have territories that overlap those of a few females, and females may have home ranges that overlap. Males do not have home ranges that overlap. However, Clark (1978) found that females tend to exclude other females from their home range and males are less likely to exclude other males. Smaller males generally have territories that are on the periphery of optimal habitat (Bearder and Doyle, 1974). Young females may have a range that is adjacent to or overlapping their mother's range (Clark, 1985). Females generally have home ranges that are smaller than males (Clark, 1985). Marking and grooming behavior are important in maintaining relationships between individuals (Rosenson, 1973; Drews, 1973). Social interactions largely occur at areas of home range overlap, sites of large gum sources, and preferred sleeping trees (Clark, 1985). Social interactions occur mostly after the first hour of feeding but can occur throughout the night (Clark, 1985). In captivity in groups with a single male, the male participated little in agonistic activity and participated greatly in social grooming, but mostly as the individual being groomed (Drews, 1973). In the wild most adult male agonistic interactions during the mating season (92%) (Clark, 1985). During the mating season adult females will only associate with males and their juveniles (Clark, 1985). Females were found to be hostile to females in estrus in captivity (Roberts, 1971). Older juveniles will follow older males around during the night, possibly to gain knowledge of food resources (Clark, 1985).

Social play in the greater galago occurs amongst juveniles, subadults, young-adult males, and adult females with juveniles (Clark, 1985). Social play includes the behavioral patterns: bite, attempted bite, manual attack, attempted manual attack, jump on, head butt, raise one arm, and rear (defensive attack posture) (Ehrlich, 1977). Social play also includes play-fighting which is mutual biting, hitting, and grasping (Ehrlich, 1977).

VOCAL COMMUNICATION:
raucous cry call: this call produced by adults sounds like a cawing or barking noise (Estes, 1991). This call is a series of repeated units that are produced over a frequency range of 40-4000 hertz (Masters, 1991). Each unit can last from 0.5-0.75 seconds (Clark, 1988). It utters the call from tall trees and the body shakes rapidly while emitting the call (Estes, 1991). These calls can be used by researchers to distinguish individuals from one another (Estes, 1991). This call is uttered most often during the mating season (Estes, 1991). This call is used for long distance communication (Masters, 1991).

alarm call: this call can take the form of the following number of noises: rattle, moan, chatter, chirp, whistle-yap, whistle, squawk, creak, knock, and sniff (Estes, 1991). These calls can last for up to an hour (Estes, 1991).

contact-rejection calls: this call can take the form of the following number of noises: hack, spit, and scream (Estes, 1991; Petter and Charles-Dominique, 1979). Intense screams could also have urination, defecation, and defensive-threat posture associated with them (Estes, 1991; Petter and Charles-Dominique, 1979). The scream is heard if an individual is attacked by a predator or conspecific, trapped in a nest, or frightened (Petter and Charles-Dominique, 1979).

distress call: this call sounds like a yell (Estes, 1991; Petter and Charles-Dominique, 1979). This is high-pitched and given in response to pain or fear (Estes, 1991). This call not only attracts other greater galagos, but also potential predators (Estes, 1991).

infant call: like the other galagines, this call sounds like "tsic" (Estes, 1991). The infant emits this to elicit contact from its mother (Estes, 1991). This call is heard from the first day of life (Ehrlich, 1974).

mother call: this call is in response to the infant "tsic" call (Estes, 1991). The call sounds like a cluck noise (Estes, 1991).

sex call: this call, emitted only by the male, is given before and after grooming (Estes, 1991). This call is low frequency and sounds like a crack call (Estes, 1991).

OLFACTORY COMMUNICATION:
foot-rubbing: this behavior is mainly performed by adult males, but sometimes juveniles will do it (Estes, 1991). An individual will rub one foot on a tree then the other (Estes, 1991). The basal part of the hindlimb may also be involved in this behavioral pattern (Bearder and Doyle, 1974). A scraping noise often occurs because of the rubbing of the feet and legs (Bearder and Doyle, 1974). It is done with urination, also with urine-washing, rhythmic urination, and chest-gland marking (Estes, 1991). The purpose is not entirely known, but the greater galago does this during social encounters and in the presence of predators (Estes, 1991).

cheek rubbing: This is when an individual will rub the cheek region against a support (Tandy, 1976). This behavior may occur with chest-gland marking and ano-genital rubbing (Clark, 1978).

chest-gland marking: this is behavior is done by both adult male and female greater galagos (Estes, 1991). Adult males have a larger chest patch than adult females (Bearder and Doyle, 1974). The gland on the chest is rubbed against tree trunks and branches (Estes, 1991). This is a highly stereotyped behavior with the greater galago rubbing its chest in hard to reach areas of the trees (Estes, 1991). Most often this behavior is done beneath a tree branch with an upward sliding type movement (Bearder and Doyle, 1974). Its function is marking of a territory, and the dominant males do this most frequently (Estes, 1991; Bearder and Doyle, 1974; Clark, 1978). This behavior is also seen when an individual is alarmed and before and after agonistic encounters (Clark, 1978). In captivity this behavior was found to always succeed sniff (Bullard, 1984). In a captive experiment, males were castrated and it was found that there was a sharp decrease in chest-gland marking behavior (Bullard, 1984). This was because of a decrease of the amount of testosterone in the body of the male (Bullard, 1984).

ano-genital rubbing: This is when an individual will drag the ano-genital region across the substrate (Tandy, 1976). This behavior is done in a forward sliding motion (Bearder and Doyle, 1974). Occasionally this behavior is performed beneath a tree branch with the ano-genital region pressed against the branch and pulled by the movement of both arms (Bearder and Doyle, 1974). This behavioral pattern occurs in both adult males and females and functions to communicate territoriality or has a sexual significance (Bearder and Doyle, 1974). This behavior is seen when an individual is alarmed and before and after agonistic encounters (Clark, 1978). This behavior often occurs with chest-gland marking (Clark, 1978). Females have been found to show a preference for performing this behavior over areas of other females' ano-genital rubs (Clark, 1978).

urine-washing: the greater galago takes its hands and cups them, and then deposits urine on them (Estes, 1991). Next the greater galago takes that urine and spreads it on the soles of the feet (Estes, 1991). When the greater galago walks now, it leaves a little bit of urine on the substrate (Estes, 1991). Males urine-wash more frequently than females do, and when the female is in estrus, the male will deposit the urine directly upon the female, but all age classes perform this behavior (Estes, 1991; Bearder and Doyle, 1974). A greater galago will urine-wash when foraging in a new area, looking at a strange object, during aggressive encounters, and social grooming (Estes, 1991; Clark, 1978). This behavior occurs more frequently in dominant individuals (Tandy, 1976). The frequency of this behavior depends on temperature, atmospheric moisture, and substrate conditions (Welker, 1973).

rhythmic urination: the greater galago does this when it is in a new area (Estes, 1991). It moves slowly while depositing a small amount of urine on the substrate (Estes, 1991). This behavior is performed more frequently by female greater galagos than it is by males (Estes, 1991).

ano-genital muzzle: This is when one individual will sniff the anal-genital region below the base of the tail of another conspecific (Tandy, 1976). Two individuals may do this behavior simultaneously (Rosenson, 1973).

sniff: This is when one individual smells the area around another (Tandy, 1976). The hands are first sniffed from below, then if not repulsed the lips and face are then sniffed (Clark, 1978). In captivity this behavior was found to precede chest-gland marking (Bullard, 1984).

VISUAL COMMUNICATION:
defensive attack posture: the greater galago does this when threatened into a corner (Estes, 1991). It stands on its hindfeet with the arms in an outstretched position, with the hands cupped; it tends to look like a boxer (Estes, 1991; Roberts, 1971). The performer of this behavior will move forward with the arms raised above the head (Roberts, 1971).

mouth-open display: This is when the mouth is slightly open and there is no sounds emitted (Tandy, 1976). During this display the teeth may or not show (Tandy, 1976). This behavior serves to communicate threat (Ehrlich, 1977).

open mouth lunge: This is behavior serves to communicate threat on the part of the performer (Eaton et al., 1973;).

folded ears: This is where the eras are folded back against the head (Ehrlich, 1977). This behavior serves to communicate threat (Ehrlich, 1977).

tail arch: This is when an individual will sit with the tail curved over the body (Ehrlich, 1977). This behavior serves to communicate disturbance (Ehrlich, 1977).

head down: This is when an individual will lower the head and then turn the body away from a conspecific (Ehrlich, 1977). This behavior serves to communicate subordinance (Ehrlich, 1977).

tucked-under tail: This is when an individual will tuck the tail under the body and it serves to communicate submission (Sauer and Sauer, 1963; cited in Tandy, 1976).

TACTILE COMMUNICATION:
nose-to-nose sniffing: the greater galago does this when first coming upon a conspecific (Estes, 1991). This is followed by nose-to-face contact (Estes, 1991).

nose-to-face contact: this occurs after nose-to-nose sniffing (Estes, 1991). An individual will touch the face of a conspecific with its nose (Estes, 1991).

lick: This is where the male will lick the ano-genital area of the female to find if she is ready to be mated with or not (Eaton et al., 1973). Adult males will also lick the scent mark left by an estrus female (Clark, 1978).

social grooming: this behavior is not as developed in the greater galago (Estes, 1991). This behavior is basically regulated to reciprocal licking (Estes, 1991). Individuals will use their toothcomb as a scraper to push along the fur and skin of another, pausing occasionally to clean the toothcomb with its tongue (Rosenson, 1973). Mothers do not use their toothcombs when grooming their infants; instead they carefully lick the infant's neck, head, flanks, and arms (Tartabini, 1991). The groomers will often support themselves by holding the fur of the groomee with one or both hands (Rosenson, 1973). Each individual deposits saliva upon one another and sometimes urine. Mutual grooming can occur, but most of the time it is alternate grooming (Rosenson, 1973). Individuals will solicit grooming by pointing the head down and holding an outstretched arm towards the potential groomer (Ehrlich, 1977). In captivity males were found to be groomed the most (Drews, 1973). Roberts (1971) found that in captivity grooming played a more important role in female-female interactions then in male-male interactions.

REPRODUCTION:
This species usually gives birth to twins, but in some areas triplets or singletons are more common in a single birth season (Bearder and Doyle, 1974). The birth season for the greater galago is at the beginning of November in the wild (Bearder and Doyle, 1974). In captivity, no defined birth season was found to occur (Bearder and Doyle, 1974). The mean gestation period for the greater galago is 128 days (Ehrlich, 1974), although Eaton et al. (1973) found that the mean gestation period is 132.8 days.

During the mating season, there is swelling of the sexual organs in the greater galago. This species has a single mating season that occurs in the month of June and lasts for two weeks (Clark, 1985). Mating starts off with the male approaching the female while emitting sex call followed by the male performing sniff (Eaton et al., 1973). The female may also sniff the male (Eaton et al., 1973). The male will then lick the female to see if see is ready to be mated with, and if she is she will crouch down and raise her perineum towards the male and divert the tail to the side (Eaton et al., 1973). If the female is not receptive to mating, then she will threaten and/or attack the male (Eaton et al., 1973). If receptive, the male will try to mount the female and in doing so will sometimes bite the back of the female gently (Eaton et al., 1973). Once the male has obtained a clasped mount, he will remain motionless for a few seconds, then start to thrust or dismount (Eaton et al., 1973). The male will start rapid pelvic thrusts to achieve an erection, and will keep thrusting until either intromission (insertion into the vagina) occurs or will dismount if intromission cannot be reached, thrusting from 30 to 80 seconds (Eaton et al., 1973). If intromission is achieved the male will reduce the thrusts to a slower speed, but will be vigorous and last from 4 to 8 minutes (Eaton et al., 1973). The female will sometimes turn around and clasp the male while he is mounted and thrusting (Ehrlich, 1977). Ejaculation occurs after the completion of the deep thrusts, and the male will maintain intromission, resting his chin on the back of the female, for several hours (Eaton et al., 1973). Every 20 minutes the male will begin the deep, slow thrusts again, resting his chin on the back of the female between the bouts (Eaton et al., 1973).

Births will occur during the day with the female staying awake when others go to sleep (Ehrlich, 1977). Before giving birth, contractions are visible and the female will lick the ano-genital area frequently (Ehrlich, 1977). The female will not make any sound when giving birth (Ehrlich, 1977). The infants are born with eyes open and have a body mass of about 40 grams (Klopfer and Boskoff, 1979; Nowak, 1999).

A major portion of an infant's time is spent in contact or near (within 15 centimeters) of its mother (Ehrlich, 1974). Mothers transport their infants orally, but this ceases when the infant is 5 weeks old (Ehrlich, 1974). The mother will grasp the infant in her mouth either between the extremities or by the infant's neck (Tartabini, 1991). At about 7 weeks of age, the infants will start to explore their surroundings, attempt to groom their mothers, and try to start rough and tumble play (Ehrlich, 1974). Weaning occurs at 3 months for the greater galago (Clark, 1985). Alloparenting has been found to occur with adult females and subadult males and females providing the care (Clark, 1985). Subadults will play with or groom juveniles while the mothers forage (Clark, 1985). Infanticide has been observed in captivity where the mother neglects the infants and infants soon die (Tartabini, 1991). Males have also been found to kill newborn infants in captivity (Ehrlich, 1977). Infanticide might occur because of the stress of living in captivity (Tartabini, 1991).

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