Thick-tailed bushbabies are mostly gumivorous and frugivorous; they are known to eat insects as well. In a study in South Africa, approximately 62% of the diet was gums and saps, supplemented by fruits and insects. The diet of O.crassicaudatus varies with locality. In the Transvaal, South Africa, insects were estimated to comprise 5% of the diet, whereas in Kenya, insects may account for 50 to 70% of the diet. One insect species which may serve as a seasonal food supply is Macrotermes falcigar, also known as large termites. When these termites are in the alate (winged) form, thick-tailed bushbabies have been observed eating them off the ground without using their hands.
Animal Foods: insects; terrestrial non-insect arthropods
Plant Foods: fruit; sap or other plant fluids
Primary Diet: omnivore
Accounts of predation on this species are lacking the literature covered here. However, as small, nocturnal mammals, it is likely that snakes, owls, and small carnivorous mammals may prey upon them.
Otolemur crassicaudatus, also known as the thick-tailed galago, is the largest galago species. Head and body length ranges from 297 to 373 mm, and tail length from 415 to 473 mm. Body size is sexually dimorphic, with males being significantly larger than females. The coloration of the fur is silvery brown to gray with the underside usually lighter in color. The fur is dense, woolly, quite long, wavy, and usually described as without luster.
The ears of O. crassicaudatus are large and can be moved independently of each other backwards and towards the base of the ear. These primates often furl and unfurl their ears, giving them a quizzical expression.
The eyes are forward pointing and large. As with most galago species, there are flat disks of thickened skin at the ends of the fingers and toes useful in grasping limbs. The fingers are long, and the toes are flattened with flattened nails. The dental formula is I 2/2, C 1/1, P 3/3, M 3/3.
Range mass: 1 to 2 kg.
Range length: 297 to 373 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Average basal metabolic rate: 2.595 W.
Species in the genus Otolemur have been reported to live in excess of 18 years in captivity. It is likely that wild individuals have a lower life expectency.
Range lifespan
Status: captivity: 18+ (high) years.
Average lifespan
Status: captivity: 22.7 years.
These animals are forest dwellers (Nowak, 1983).
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: rainforest ; scrub forest
Thick-tailed galagos, or bushbabies, are found in East Africa from southern Sudan to eastern South Africa and through southern Angola.
Biogeographic Regions: ethiopian (Native )
These animals are clearly important in local food webs. They prey upon insects, controlling the growth of insect populations. In additon, as a prey species, O. crassicaudatus may have a positive impact on the populations of its predators.
These animals, like other galagos, may occasionally be hunted as food. However, for the most part, they have no economic importance to humans.
Positive Impacts: food
There are no significant adverse effects of O. crassicaudatus on humans.
Although this species is rated "Lower Risk" on the IUCN Redlist, it is losing habitat due to humans clearing the land for farming and grazing animals.
As with all primates, galagos are listed in in Appendix II of CITES, limiting international trade in the animals or their parts.
US Federal List: no special status
CITES: appendix ii
IUCN Red List of Threatened Species: least concern
This galago communicates using several vocalizations. The young make a soft clicking sound to their mother. Adults make a louder clicking noise to call to other adults. There are also loud cries, barks, and a high-pitched alarm call.
Thick-tailed galagos also communicate through olfactory signals. They urine mark and urine wash. Urine washing is a behavior that spreads the urine all over the hands and feet to leave the scent over the entire space through which the animal moves (Nowak and Paradiso, 1983).
In addition, all galagos are known to have visual communication (body postures and facial expressions) and tactile communication (primarily grooming).
Communication Channels: visual ; tactile ; acoustic ; chemical
Other Communication Modes: scent marks
Perception Channels: visual ; tactile ; acoustic ; chemical
In most types of galagos, mating can be either monogamous or polygynous. The deciding factor appears to be the population density. Males tend to maintain larger home ranges than do females. They mate with females whose ranges are encompassed by their own.
Mating System: monogamous ; polygynous
The birth season of thick-tailed galagos varies according to locality. For example, breeding is restricted to November in the Transvaal, but occurs in August and September in Zambia. Pregancies peak in August in Zanzibar and Pemba. Female estrous cycles last approximately 44 days. Gestation is 133 days.
Litter size is generally 2 young, but can be 3. Females reach sexual maturity at 2 years of age. Because male competitive behavior is usually related to size in galagos, it is likely that males reach reproductive age somewhat later than do females.
Breeding interval: The animals likely breed once annually.
Breeding season: The birth season of the thick-tailed galago varies according to locality.
Range number of offspring: 2 to 3.
Average gestation period: 133 days.
Average age at sexual or reproductive maturity (female): 2 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
Average birth mass: 43.2 g.
Average gestation period: 130 days.
Average number of offspring: 1.5.
Average age at sexual or reproductive maturity (male)
Sex: male: 639 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 495 days.
After birth, females leave their young in the tree while they leave to forage. They produce a rich, energy-dense milk, especially in comparison with anthropoid primates. This may be related to their lifestyle, as anthropoid primates carry their young during lactation and this galago does not (Tilden, 1997; Nowak, 1983). The role of the male in parental care has not been described, but through defense of his home range, he may unintentionally help to protect and defend the young within the territory.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)
The thick tailed bushbaby (Otolemur crassicaudatus), is a nocturnal primate whose child-like cries and thick tails gave rise to its name.It is the largest of the bushbaby species.This bushbaby has silvery brown to gray fur, large eyes and large ears that often furl and unfurl – giving the bushbaby a quizzical expression.
Thick tailed bushbabies are typically found in coastal or riverine forests as well as savannah highlands.Naturally, they are physiologically adapted for life in the trees.Bushbabies have long fingers and flattened toes that end with thickened skin – this aids them in scaling trees and grasping tree limbs.Their diet varies according to their locality but in SA they feed primarily on gum and often supplement their diet with insects and fruit.
The breeding season of thick tailed bushbabies also varies according to locality.However, a litter size of two individuals is fairly constant across the different localities. Thick tailed bushbabies are the most social of all known bushbabies.Social behaviour includes tail pulling, wrestling, non-aggressive biting, chasing, walking and pouncing.These bushbabies sleep together in nests during the day and split up at night to feed.
The IUCN lists the thick tailed bushbaby as a species of least concern because it has no major threats.
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The brown greater galago (Otolemur crassicaudatus), also known as the large-eared greater galago or thick-tailed galago, is a nocturnal primate, the largest in the family of galagos. As opposed to smaller galago species it would climb, walk or run rather than leap.[3]
Two subspecies of Otolemur crassicaudatus are recognised:[1]
The IUCN considers the silvery greater galago as a third subspecies, O. c. monteiri.[2] Other sources treat it as a separate species, though with "misgivings".[4] The IUCN Red List assesses all three forms individually as Least Concern.
This species has a rounded head with a short, wide snout, very large ears that can be moved independently and relatively large forward binocular eyes.[5] They possess flat thickened skin pads at the ends of their fingers and toes for grasping limbs. The fingers are long and toes are flattened with flattened nails. The dentition formula is I 2/2, C 1/1, P3 3/3, M3/3.[6]
The thick fur is highly variable in color, depending on the subspecies: O. c. crassicaudatus exhibits dorsal pelage ranging from buff to gray extending to the face, flanks and limbs. The ventral fur is cream colored, and the tail has a darker tip. The hands and feet are darkened except on the digits. O. c. kirkii exhibits fur ranging from brown to grey on the dorsal surfaces. Ventrally, the fur is cream to yellow colored. The tail is usually light brown in this subspecies and the feet and hands lack darkening pattern.[5][7]
The brown greater galago has a head-and-body length of 26 to 47 cm (32 cm on average), a tail length of 29 to 55 cm, and a weight of 0.5 to 2 kg. The brown greater galago exhibits sexual size dimorphism with males being larger than the females. This is due to bimaturism, a longer period of growth in the male, on average 84.5 more days. While males and females galagos grow at the same rate, this longer growth period results in males averaging 16% more body mass than females.[8] On average females weigh 1.2 kg (2.6 lb), and males 1.5 kg (3.3 lb).[9]
This species is common in Southern and East Africa. The largest populations are found in Angola, Tanzania, southern Kenya and the coast of Somalia. The brown greater galago lives in tropical and subtropical forest, preferring riverine and coastal forest, but it can also be found in the woodland savannah.[5] The subspecies display different ranges: O. c. crassidautus is only found in the KwaZulu-Natal region. O. c. kirkii is found from Massangena north to Vila Coutinho, Mozambique and Malawi.[7]
The brown greater galago is a nocturnal, arboreal animal.[9] During the day, it rests 5 to 12 meters above the ground in a dense tangle of creepers or in the hollow of a tree, rarely on an exposed branch. Female galagos will make nests, leafy platforms with foliage above to shelter their young.[7] An individual galago may have several sleeping sites throughout its home range. At night, it emerges to forage for food. It moves quadrupedally through the trees or bush. This species is capable of short jumps from tree to tree when necessary.[7] Its diet consists of fruit (like berries, figs), seeds, acacia gum, flowers, insects, slugs, and even reptiles and small birds. An individual galago on average spends 50% of its time each night traveling and only about 20% of its time foraging. It will often follow the same patrol pathway every night.[7] Galago lifespan in captivity is 18 years or more. It is likely that life expectancy in the wild is lower.[6]
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This species is solitary, living in a home range of a few hectares; however, there is some overlap with other individuals. Males have territories that overlap with a few females and females may have home ranges that overlap, but male territories generally do not overlap.[7] Males tend to have a larger territory than females. The territory is marked by urine and a scent produced in a gland in the chest.[9] Social interaction generally occurs at sites of range overlap, sites of large gum resources or prime sleeping trees. Social play is also exhibited by juveniles, sub adults and adult females with juveniles.[7] Social grooming is absent in the greater galagos compared to other primate species. It is instead filled with a behavior known as reciprocal licking to clean each other's fur.[7]
Vocal communication is very important in galago species with significant research systematically identifying types of calls including: raucous cry call, alarm call, contact rejection calls, distress call, infant call, mother call, advertising call.
Male galagos species possess very distinctive penile morphology that can be used to classify species.[10] In O. crassicaudatus, the penis is on average 20 mm in length and increases in width towards the distal tip. The baculum clearly protrudes from the end. The glans and shaft are covered in single keratinised penile spines that point towards the body.[11][12][13]
During mating season which occurs in June, the female goes into estrus for approximately 2 weeks. She uses an advertising call to indicate her receptivity. Males approach and copulate repeatedly with the female and maintain intromission with the female for several hours.[7] Mating patterns can be either monogamous or polygynous, often determined by the overlapping of host ranges and competing of males for best territories.[6] Females typically give birth to 2 young, sometimes 1 or 3. The gestation period is on average 133 days. The female typically reaches sexual maturity by 2 years of age. Because of competition between males based upon size males usually reach reproductive age later than females.[6] After birth, the mother leaves the young to forage and returns nourishing the young with nutrient rich milk. The juveniles typically remain with their mother until they reach close to sexual maturity.[6]
The brown greater galago is listed as Least Concern by the International Union for Conservation of Nature (IUCN). The species is thought to be common in well managed protected areas. The only major threat to the species is hunting for bushmeat. Habitat fragmentation is increasing across their range, with sugar cane and forestry in South Africa being a main cause.[2]
The brown greater galago (Otolemur crassicaudatus), also known as the large-eared greater galago or thick-tailed galago, is a nocturnal primate, the largest in the family of galagos. As opposed to smaller galago species it would climb, walk or run rather than leap.
