Manis giganteagiant pangolin

Geographic Range

Manis gigantea is located in the western to central regions of Sub-Saharan Africa. Their western range includes Senegal along the coastline all to way to central Gaban and Angola and their central range includes Democratic Republic of Congo, Uganda and Rwanda. (Dorst and Dandelot, 1972; Mediannikov, et al., 2012)

Habitat

Giant pangolins are found in forests and savannas and seek shelter under piles of debris and/or burrows. The burrows can be several meters deep and are made either by themselves using their powerful forelimbs or they inhabit abandoned burrows made by another animal. They are restricted to these regions in Sub-Saharan African because of the constant, habitable environment for ants and termites, their only food source that they depend on all year round. (Challender and Hywood, 2012; Dorst and Dandelot, 1972)

Physical Description

The largest and heaviest of all pangolins, M. gigantea weighs 30.0-35.0 kg. It has an elongated body with a thick tail covered with keratinized epidermal cells in the form of overlapping scales. Their average body length is 152.4 cm and have a quadrupedal gait. They use their strong heavy forelimbs to dig burrows and nests for shelter and food. In response to their food habits their head is long, narrow, external pinnae are absent, thick heavy eyelids protect the eyes and they have no teeth. Since they are toothless, the muscles that aid in chewing and biting, the masseter and temporalis, are absent. When protruded, the maximum length of the tongue is 70 cm and when it is retracted it lays ventral to the thorax and trachea and stretches all the way down to the abdomen. Due to the incredible length of the tongue, when retracted, a portion of the tongue is folded into the cervical region, creating a bulge on the outside of the neck. The tongue is covered with sticky saliva secreted by a large submandibular gland to trap ants and termites. The hyoid bone functions to scrape off the trapped ants and termites and the stomach is lined with a hard laminated epithelium to crush insect exoskeletons.

On the fore feet there are three well-developed claws (the first and fifth digits are reduced) which are curved outwards to aid in digging. The dorsal surface of the foot is covered with scales while the ventral side of the foot has dried wrinkled skin with a granular pad. The hind feet have 5 digits with short claws that form a curved line. The scales are grey-brown and are usually 4-5 inches (10-13 cm) long. They extend across entire dorsal surface of body but are absent on the ventral side of body and the inner surface of the limbs. Compared to other Manidae species, the tail is proportionally shorter than the body. The tail is also thick at the base, pointed at the tip, and covered entirely in scales. The lateral sides of body contain 15-19 scales, with the largest scales found on the middle of the back, shoulders and thighs, and the smaller scales occurring on the legs and tail to allow easier movement. The remaining portion of body that is not covered with scales is pinkish-grey with fine strands of hair. The scales exhibit anti-adhesion and anti-wear properties against soil and rock, which allows them to easily dig into the ground.

Manis gigantea is homoeothermic and able to maintain an internal body temperature range of 26.5-34.5 degrees Celsius in ambient temperatures of 17-36 degrees Celsius. Manis gigantea, like all pangolins, have little body hair and a slow metabolism, making them susceptible to temperature changes, another reason why they are found in areas of stable temperatures. There are no obvious signs of sexual dimorphism. Sex differences in body length or mass could be present but there is currently no data available. (Botha and Gaudin, 2007; Challender and Hywood, 2012; Doran and Allbrook, 1973; Dorst and Dandelot, 1972; Heath and Coulson, 1997; Jones, 1973; Kingdon, et al., 2013; Nowak, 1991; Pocock, 1924; Tong, et al., 1995)

  • Range mass
    30.0 to 35.0 kg
    66.08 to 77.09 lb
  • Average length
    152.4 cm
    60.00 in

Reproduction

Giant pangolins are solitary except during the mating season. Their timid behaviour has made them hard to study in general but especially so in regards to reproductive behavior. Little is known about reproduction in M. gigantea but there has been some research on a similar and closely related African Manidae species, Manis temmincki, the ground pangolin, which is likely to have many similarities to giant pangolins.

Ground pangolins (Manis temmincki) are terrestrial ground-dwelling pangolin species found in sub-Saharan Africa, primarily in the savannas. Their range extends through southern and eastern Africa and they do not occur sympatrically with giant pangolins. Ground pangolins are smaller than giant pangolins and partly diurnal. The following reproductive information is data for ground pangolins. Ground pangolins are typically solitary until the mating season, which occurs from May to July during the dry season. Male-male competition takes place during the breeding season, and the female mates with the winner. Males will mate with many females but the number of mates per female is unknown. Males are more motile than females, who remain in their own home ranges during the breeding season. (Dorst and Dandelot, 1972; Heath and Coulson, 1997; Nowak, 1991; Pietersen, et al., 2014)

Nothing is known about reproduction in giant pangolins. However, in closely related ground pangolins (Manis temmincki) there is just one offspring per gestation period (two offspring is rare). A gestation period of 139 days was observed at the Bloemfontein Zoo in South Africa. Two mammary glands are present on the ventral side of the body between the two forelimbs. Only two ground pangolin offspring have been observed at the Bloemfontein Zoo. The first one, where the time of birth was unknown, weighed 425 g and was 17.78 cm long. The second baby weighed 340 g and was 15.24 cm long at the time of birth. The young will cling onto the back of the mother after four weeks and will stay attached to the mothers back for up to 6 months. It is believed that sexual maturity is reach at one-two years in ground pangolins

Reproduction has only been observed in unique cases in captivity. Unfortunately, all young pangolins at the Bloemfontein Zoo died at a young age due to health complications. As pangolins of all ages do not survive long in captivity nothing is known about their age at independence, sexual maturity, and time of weaning. The adults did not survive long enough to determine patterns and features in their reproduction. (Dorst and Dandelot, 1972; Ee, 1966; Hua, et al., 2015)

  • Breeding interval
    Breeding interval is unknown.
  • Breeding season
    Breeding season may occur from May to July.
  • Average weaning age
    4 weeks

Mothers will carry their young on their back while they are growing or keep them wrapped inside the base of their tail. Very little has been observed in the wild but in one case of a ground pangolin (Manis temmincki) in captivity (Bloemfontein Zoo), a mother was very protective and aggressive when approached by zoo employees. The mother used clawed forelimbs to attack whomever came near and curled into a ball with her young in the center. As mentioned before, no offspring or adult has survived in captivity long enough to observe parental investment past a limited number of weeks or months. (Dorst and Dandelot, 1972; Ee, 1966)

  • Parental Investment
  • precocial
  • female parental care
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

The longest a giant pangolin has lived in captivity is four years, roughly the same lifespan of other pangolin species in captivity. The longest record of a pangolin lifespan (species unknown) in captivity is 12-13 years but this record is unusual. Health complications are the leading causes of fatality. Too much interaction and disturbance by humans, especially during the day, has been shown to increase stress levels significantly in captive pangolins. These high stress levels can compromise their immune systems and make them more susceptible to disease and infections. Causes of death range from gastrointestinal diseases, pneumonia, parasites, and skin disease.Their digestive systems are highly specialized for a high fat, high protein and high calorie diet which can be hard to mimic with artificial food.

The lifespan and common cause of death in the wild, excluding human hunting, of giant pangolins is unknown. Putting into consideration their observed low reproductive rate of just one offspring per gestation it is possible that their natural lifespan is long but further research is required. (Challender and Hywood, 2012; Hua, et al., 2015)

  • Range lifespan
    Status: captivity
    4 (high) years
  • Typical lifespan
    Status: captivity
    1 to 1460 days

Behavior

In the wild giant pangolins are timid, nocturnal, solitary species spending their days concealed and asleep in their burrows. Even though they are found in and around forests, giant pangolins never climb trees. Giant pangolins are nocturnal, searching for food at night and occur in low densities. When feeding they closes their eyes, nostril holes and ears to protect themselves from defensive attacks by ants or termites and they can shake ants and termites off of their scales. Giant pangolins are sensitive to temperature changes and have slow metabolisms plus very little body hair. Thermoregulation is usually not a problem because the ambient temperature in their natural environments stays relatively constant but if temperatures are too low in captivity, they are incapable of warming themselves. (Dorst and Dandelot, 1972; Swart, et al., 1999)

Home Range

In ground pangolins (Manis temmincki), males have larger home ranges than females and the home ranges among same sexes are adjacent to each other with little overlap. The overlap between male and female home ranges is high and during the mating season males will move into female home ranges. Ground pangolins (Manis temmincki) also use many different burrows found within their home range. Young pangolins will set up their initial home range within their mother's range and females will remain in their natal home ranges for longer periods of time than males. In ground pangolins (Manis temmincki) in South Africa, the average home ranges for adult male and female adult ground pangolin are 10.0 ± 8.9 km² and 6.5 ± 5.9 km² respectively and for young male and female ground pangolins are 7.1 ± 1.1 km² and 6.1 ± 4.0 km² respectively. The availability of space may be different in more western and central in Africa where Manis gigantea is found. (Heath and Coulson, 1997; Pietersen, et al., 2014)

Communication and Perception

Giant pangolins repeatedly protrude and retract their tongues to get a sense of the environment. The tip of the tongue is very sensitive to touch and is used as a form of perception. There are no data indicating if and how they communicate during the breeding season. (Doran and Allbrook, 1973)

Food Habits

Giant pangolins are myrmecophagous mammals, meaning a diet specialized in ants and termites. All pangolin species require a diet high in fat and protein. The specificity of their diet is one reason why it is so challenging to keep them alive in captivity. They forage at night and are able to dig deep into the soil and destroy the underground nests of ants and termites to eat directly from the nest. They sometimes consume soil and rocks when foraging but suffer no adverse effects. (Botha and Gaudin, 2007; Hua, et al., 2015; Swart, et al., 1999)

  • Animal Foods
  • insects

Predation

The scales covering the majority of their body serves as a protective layer from predators. In the event of a threat they will curl up into a tight ball with just the scales exposed to the outside. Once rolled into a ball they are virtually impossible to uncurl and can cause deep cuts from their scales by contracting their muscles. Another form of defense is the ejection a foul-smelling liquid from the anal region to repel predators. Giant pangolins resort to these defense mechanisms if they are unable to make it to their burrow in time. Giant pangolins are hunted by humans but other predator’s in the wild are unknown. (Challender and Hywood, 2012; Nowak, 1991; Soewu and Ayodele, 2009)

Ecosystem Roles

As mentioned previously, giant pangolins specialize in ants and termites, eating a significant amount of these invertebrates every year. In doing so, they play an important role in regulating insect populations. Giant pangolins also act as an important host for the parasitic tick, Amblyomma compressum. This tick exhibits a high selectivity towards African pangolins, especially giant pangolins. Rickettsia africae is a type of bacteria in spotted fever group rickettsiae found commonly in A. compressum. It is common for giant pangolins to carry an infected tick on their skin and scales and play an important role in the spread of this bacteria to different hosts. (Hua, et al., 2015; Mediannikov, et al., 2012)

Commensal/Parasitic Species

Economic Importance for Humans: Positive

Humans benefit from giant pangolins in many different ways. The first is that it provides a cheaper alternative of protein for local populations. In general, all types of bushmeat are more affordable for locals and hunting bushmeat provides income for local individuals. The traditional medicinal use of pangolins is extensive in Africa. Unlike other animals used for traditional medicine, every body part and age set of giant pangolins can be used for a specific purpose. Medicinal properties can range from treating stomach disorders, preventing miscarriages and other reproductive complications, treating mental disorders and even protection from spiritual attacks and casting love spells. A wide range of medicinal treatments using pangolins are common in both African and Asian traditional medicine. However, it is important to note that the efficacy of these traditional uses is not proven. One benefit to humans that may go unnoticed is how much giant pangolins and other pangolin species in Africa effectively control and regulate insect populations, which have the potential to be a significant nuisance to humans. (Soewu and Ayodele, 2009; Willcox and Nambu, 2007)

Economic Importance for Humans: Negative

The species Amblyomma compression is a tick with a high specificity for M. gigantea. These ticks are parasites that are often hosts to spotted fever group (SRG) rickettsia, a bacterium responsible for illness among travellers and locals in Sub-Saharan Africa. In one study, three pangolins (M. gigantea) contained a total of 12 A. compressum and approximately 50% of them were infected with the bacteria Rickettsia africae. Rickettsia africae is a dangerous bacterium responsible for African tick-bite fever, a serious health concern for humans alongside malaria. Human contact with pangolins has increased due to higher demand in bushmeat, body parts for medicinal purposes and poaching for illegal trading to other countries. (Freedman, et al., 2006; Mediannikov, et al., 2012; Soewu and Ayodele, 2009)

Conservation Status

Under the IUCN List M. gigantea was classified as near threatened in 2008 and is now classified as Vulnerable with declining population numbers continuing. The U.S. Fish and Wildlife Services even go on to say that pangolins may be “among the most trafficked mammals in the world”. All pangolin species are listed in Appendix II of Convention of International Trade in Endangered Species of Wild Fauna and Flora. Despite their dwindling numbers, there continues to be many seizures of unauthorized exports of African pangolins to Asian markets. The detection of pangolin smuggling is low and it is believed that the rate of illegal poaching occurring in Africa is far greater than currently documented. Increases in African pangolin poaching to ship to Asian markets are a result of the native Asian species being over hunted. There are no data on M. gigantea on the US Federal list but M. temminckii (the ground pangolin), another African pangolin closely related to M. gigantea is listed as Endangered on the US Federal list.

Pangolins are used extensively for medicinal purposes across Africa. In one study, a total of 178 pangolin carcasses were sold in the African market for traditional purposes, of those recipients 90% were unaware of the conservation status of pangolins, 55% only had a primary education, 14% admitted to paying hunters to deliberately hunt pangolins when needed and over 98% of these hunters had no other means of income, Most (95%) of recipients were apathetic towards pangolins, believing that all animals on earth were meant to serve a purpose for humans. This mentality, the high demand for poaching, and a lack of insight on their conservation status and life history traits poses a huge threat to M. gigantea and all of the other pangolin species. Another concern is that all age classes, juvenile to late adult, are used in medical treatments, with each age class serving specific purposes. Alongside traditional medicine, pangolins are important as a local bushmeat.

Another concern to conservation is the immense difficulty in keeping pangolin species alive and healthy in captivity. Many zoos have attempted and almost all species have died quickly and painfully from disease and other causes. If a species were to become extinct in the wild, there is currently no hopeful alternative of a captive breeding program. If the rate of hunting does not change, M. gigantea will likely become extinct in the near future. Educating local populations and the rest of the world about the conservation status of M. gigantea and its life histories may help alleviate hunting pressures and decreased commercialization in Africa. (Brautigam and Howes, 1994; Challender and Hywood, 2012; Kwame Boakye, et al., 2015; Sodeinde and Soewu, 1999; Soewu and Ayodele, 2009; Willcox and Nambu, 2007)

Other Comments

Family Manidae was originally included in the order Edentata alongside sloths, armadillos and anteaters because of its lack of teeth, but these similarities are now considered to be a result of convergent evolution. Giant pangolins and the rest of Family Manidae are placed in their own separate order Pholidota and are more closely related to order Carnivora. According to local legends, pangolins will settle into an ant’s nest and crush the ants that reach under its scales. Keeping the now dead ants underneath their scales, they will then submerge themselves in water and allow the ants to float to the top to consume them, creating what is called an "ant bath". (Nowak, 1991)

Contributors

Claire Gallagher Fenton (author), University of Manitoba, Jane Waterman (editor), University of Manitoba, Tanya Dewey (editor), University of Michigan-Ann Arbor.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

causes disease in humans

an animal which directly causes disease in humans. For example, diseases caused by infection of filarial nematodes (elephantiasis and river blindness).

chemical

uses smells or other chemicals to communicate

drug

a substance used for the diagnosis, cure, mitigation, treatment, or prevention of disease

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

food

A substance that provides both nutrients and energy to a living thing.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

polygynous

having more than one female as a mate at one time

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

young precocial

young are relatively well-developed when born

References

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