Greater Bamboo Lemur, Prolemur simus
GREATER BAMBOO LEMUR
Prolemur simus
Geographic Distribution and Habitat
The greater bamboo lemurs, also known as broad-nosed bamboo lemurs or broad-nosed gentle lemurs, are endemic to Madagascar. This large island, located approximately 250 miles (400 km) off the coast of East Africa, is an important biodiversity hotspot. It is home to numerous animal and plant species that do not exist anywhere else in the world.
Fossil records indicate that 90,000 years ago, there were about one million greater bamboo lemurs in Madagascar. In fact, it is the lemur species for which science has found the greatest number of fossils. These lemurs roamed the northern, northwestern, central, and eastern parts of the Great Red Island (as Madagascar is also known). Severe climate events and a growing human population impacted their habitat and contributed to their decline. By the late nineteenth century, they were restricted to the eastern rainforest, near the Bay of Antongil, and to the Southeast near Nandijhizana. Their population declined to such a degree that in the 1950s, the species was considered extinct.
However, in 1972 two Frenchmen captured a pair of them. These two greater bamboo lemurs were placed in a zoo where they quickly died. Then, in 1986, Duke University announced the species had been rediscovered. Dr. Patricia Wright observed greater bamboo lemurs in the forests of Ranomafana and Kianjavato. She described them as “tree-dwelling creatures, the size of a large cat, but with rusty red fur and golden cheeks” and “a raucous, crow-like call.” At the time, she guessed there were no more than 200 individuals in existence.
Today, greater bamboo lemurs are mostly found in southeastern Madagascar, where bamboo is most abundant, drinking water is available, and the dry season is the shortest. Their current territory represents less than 4% of their original range. Nonetheless, there is evidence that they are more widely distributed than previously thought. The current population is estimated at about 1,000 individuals. Their presence has been documented at elevations ranging from 395 feet (120 m) to 5,250 feet (1600 m) in rainforest corridors between Ranomafana National Park and Andringitra National Park. They are also present near rivers in the Vatomandry, Mahanoro, Mananjary, and Vondrozo Districts. Five of the sites (Kianjavato, Morafeno, Karianga, Mahasoa, and Evendra) are unprotected and degraded forests.
Prolemur was named a distinct genus in 2001, specifically for this greater bamboo lemur species. Prior to that determination, the greater bamboo lemur was included in the Hapalemur genus, with the gentle and bamboo lemurs, and called Hapalemur simus.
Size, Weight, and Lifespan
Greater bamboo lemurs are the largest of the bamboo lemurs. It is difficult for a lay observer to distinguish between males and females because they are almost the same size. Males are only slightly larger, with an average weight of 6 pounds (2.75 kg) compared to the females’ 5.7 pounds (2.61 kg). Their body is 16–18 inches (40–45 cm) long and their tail has a length of 17–19 inches (43–48 cm).
The span of a generation is estimated at 10 years. Longevity in the wild is not documented, but the oldest greater bamboo lemur in captivity passed away at the ripe old age of 24.
Appearance
The greater bamboo lemur’s face is round and the snout has large slanted nostrils. Their ears are adorned by tufts of soft white fur. Their almond-shaped eyes are hazelnut in color, but at night they appear bright because they have a surface that reflects light and allows them to see quite well in the dark. In studying their teeth, scientists have discovered these lemurs have large teeth and their premolars look a lot like molars—a dental trait shared with the giant and red pandas.
These beautiful lemurs have a gray coat with rusty chocolate highlights at the shoulders. Their fur is short and dense, which keeps them fairly dry, even when it rains hard. Their long furry tail helps them balance in the trees as they travel in the canopy. Their long and strong legs allow them to leap vertically from tree to tree while foraging. Their arms are shorter and much thinner than their legs. Feet and hands each have five digits. The second digit of each foot is referred to as a “toilet claw,” which they use to clean their fur.
Diet
The similarities scientists found between greater bamboo lemurs’ and pandas’ teeth are explained by their very specialized diet. Both species specialize in bamboo. Greater bamboo lemurs survive almost exclusively on large-culled bamboo, constituting 95% of their diet. Because the bamboo they eat is quite large, the lemurs have been observed holding a stem with both hands while painstakingly biting the bamboo to break it open. They eat shoots, young and mature leaves, culms, and piths. Recent studies show that culm feeding occurs mainly between August and November, while shoot feeding starts at the onset of the rainy season.
The most common bamboo species they consume are: giant bamboo, found in mid- to high-elevation rainforests; evergreen bamboo, abundant in lowland secondary habitats; and bamboo that grows along rivers. It is estimated that greater bamboo lemurs feed on at least 29 bamboo species, of which 9 are woody and 20 are flowering grasses found on the forest floor and along dirt roads. In fact, these lemurs spend 25–30% of their time feeding on the ground. Greater bamboo lemurs have even been observed eating pineapple plants. There is also evidence that they are able to supplement their diet with fruit, flowers, soil, and fungi.
Various bamboo species contain different levels of cyanide—a poisonous chemical that inhibits breathing and causes death. The giant bamboo that these lemurs eat every day contains the highest levels of cyanide of all bamboo species. Surprisingly, the amount of poison these lemurs ingest daily is up to 48 times the lethal dose for a mammal their size. This is difficult and dangerous food to process, yet these lemurs have evolved to do just that. Bamboo is very rich in protein and the grasses the great bamboo lemurs consume don’t contain a lot of tannins. The lack of tannin allows lemurs to process high levels of protein, which, according to recent studies, are much needed for lemurs to detoxify. These creatures’ complex digestive system also plays an important role in their ability to safely process cyanide, eliminate most of it through urination, and increase their tolerance to residual poison.
Behavior and Lifestyle
Greater bamboo lemurs are cathemeral, which means they are active day and night, all year round.
They are arboreal but they also spend time on the ground. The time they spend foraging or traveling on the ground depends on the season. It usually peaks during the summer, which coincides with the months of January in Kianjavato and February in Ambalafary and the Ranomafana National Park.
Their home range, which can span 65 to 125 acres (27–50 ha), is larger during the summer than during the winter. The size of their home range depends on the distribution of bamboo plants and the availability of drinking water.
Greater bamboo lemurs have occasionally been observed sharing an overlapping territory with groups of red-fronted lemurs and black-and-white ruffed lemurs.
Fun Facts
Scientists are using cameras, placed at different levels of the canopy, to observe arboreal creatures like the greater bamboo lemur.
Almost all greater bamboo lemurs in captivity are descendants of two individuals born in the wild.
These gregarious lemurs live in polygamous groups that vary in size. Some reports indicate that the mean group size includes up to 8 individuals, others report that they can include up to 15, and others yet confirm much larger groups of up to 28. More observations are needed and it is possible that the size of groups varies depending on location and time of year. They may be larger during breeding season, for example, and smaller when males disperse to find or form other groups.
This is the only lemur species in which males are dominant. In fact, during feeding bouts, some males were observed stealing the bamboo shoots that females had worked hard to pry open.
Primatologists have recorded at least nine calls that these animals use in different circumstances. They emit contact calls that help individuals in a group keep in touch and alert calls to warn others of aerial or land predators. Infants also have their own calls to indicate distress.
Like most other primates, greater bamboo lemurs communicate with scent-marking. Facial expressions may also be used to communcate. For example: when they are aggressive or fearful, they pull their ears back.
Greater bamboo lemurs are polygynous. This means that males can mate with several females. Breeding season takes place between April and June. The gestation period is estimated at 150 days. Once females are ready, they often leave the group for a few days and return after giving birth to a single infant. Twins are extremely rare. Most births occur in October and November.
Males usually disperse from their natal group once they are three or four years old. Females become mature at about two years of age and usually have their first baby at three. Once they have given birth, they don’t have another baby for at least a year—or even a bit sooner if an infant dies.
Infants stay close to their mothers for the first two weeks of their lives, during which time infant mortality is high (40% to 50% every year) because they are at risk of dangerous falls while they cling to their mothers’ bellies or backs. The risk of deadly falls diminishes as the baby reaches two months of age, which coincides with the time they are weaned. Once they are weaned, they can feed on their own, but still rely on adults to break bamboo culm and get to the inner softer part.
Offspring remain with their mother until they are about 5 months old, when they have full locomotor independence.
Since greater bamboo lemurs eat some fruit, they can be considered seed dispersers. They also play an important role in thinning the forest by breaking bamboo. Finally, they are a source of food for a few predators—like the fossa and some raptors.
The International Union for Conservation of Nature lists the greater bamboo lemur as Critically Endangered (IUCN, 2018), appearing on the IUCN Red List of Threatened Species. In fact, this species has been classified as Critically Endangered since 1996. The greater bamboo lemur is also considered one of the top 50 most evolutionarily distinct and endangered mammals by the ZSL EDGE Programme. EDGE is an international conservation initiative developed by the Zoological Society of London, UK. Its goal is to protect the most unique species on the planet.
Greater bamboo lemurs are threatened by human activities. Not only are they hunted for food—with slingshots, spears, and snares—but their habitat continues to shrink every year due to slash-and-burn agriculture, illegal logging, mining, industrial crops, and bamboo cutting. Madagascar lost 37% of its forest cover between 1973 and 2014. What used to be lush continuous forests are now disconnected fragments of forested areas.
Forest fragmentation poses serious risks for highly specialized feeders like greater bamboo lemurs. Indeed, the bamboo species the lemurs need to survive may soon disappear from their habitat. Madagascar regularly experiences severe weather events that may destroy all its food sources. Cyclone Joanna and tropical storm Irina, which occurred in succession in February 2012, uprooted many acres of trees and bamboo, flooded rice fields, destroyed schools and bridges, and left wildlife and humans alike at risk of famine and without shelter. Climate change will cause more frequent drastic weather events like these. Scientists expect climate change will impact seasonality and bamboo availability due to prolonged dry seasons. They estimate that bamboo forests will decline by 50% between now and 2080.
Paradoxically, eco-tourism poses yet another threat to bamboo lemurs. Although such activity is a source of revenue for people and can help support conservation efforts, frequent visits to a site damage bamboo forests and greatly disturb indigenous wildlife.
The greater bamboo lemur is listed in Appendix A of the Convention on International Trade in Endangered Species (CITES), an international agreement between governments whose goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival.
The Aspinall Foundation NGO has been working closely with local partners in Madagascar to protect the greater bamboo lemur—among other endangered species. One of their projects is called “Saving Prolemur simus” (named after the scientific name of the greater bamboo lemur). It focuses on key areas, such as the collection of data in the central and eastern rainforest belt, the maintenance of rainforest corridors, and the protection of isolated groups of greater bamboo lemurs. The foundation provides conservation workshops and has been collaborating with Conservation International and local authorities to ensure the sustainable management of zoned and protected forest corridors. Local rangers patrol specific sites to prevent illegal logging, mining, and hunting. These rangers also document the areas where greater bamboo lemurs live and monitor group size, composition, and behavior. To facilitate locating these animals, radio collars are being used in several groups without negative impact on the lemurs.
The conservation of forest corridors is paramount to maintaining gene flow between different groups of greater bamboo lemurs and preventing population decline. It is therefore important to protect them and ensure they are granted higher protection status than other forested areas. Researchers are also evaluating the feasibility of using isolated populations of greater bamboo lemurs as a source for potential semi-captive breeding and reintroducing gene diversity in the wild by translocating some of these animals.
References:
- https://www.iucnredlist.org/species/9674/115564770
- Grazing lemurs: exhibition of terres- trial feeding by the southern gentle lemur, Hapalemur meridionalis, in the Mandena littoral forest, south- east Madagascar – Timothy M. Eppley, Giuseppe Donati
- https://animaldiversity.org/accounts/Prolemur_simus/
- Population survey of the Greater lemur (Prolemur simus) at Kianjavato Classified Forest – Susie M. McGuire, Carolyn A. Bailey, Jean-Nor- bert Rakotonirina, Lamaherisolo G. Razanajatovo, Jean F. Ranaivoarisoa, Lisa M. Kimmel, Edward E. Louis, Jr.
- Impact du tourisme sur Prolemur simus à Talatakely, dans le Parc National de Ranomafana – Jeanne Aimée Norosoarinaivo, Chia Tan, Lydia Rabetafika, Daniel Rakotondravony
- Rapid primatological surveys of the Andringitra forest corridors: direct observation of the greater bamboo le- mur (Prolemur simus) – Kira E. Delmore, Margaux F. Keller, Edward E. Louis Jr., Steig E. Johnson
- Habituation of Greater bamboo lemurs (Prolemur simus) in the Vatovavy forest, Madagascar – Ando N. Rakotonanahary, Nicole V. Andriaholinirina, Solofonirina Rasoloharijaona, Jean F. Rajaonarison, Ryan A. Hagenson, Timothy M. Sefczek, Cynthia L. Frasier and Edward E. Louis Jr
- Fragmentation Reduces Dietary Diversity, yet Expands Dietary Options of Madagascar Lemurs – Peyton Schrag
- Saving the Critically Endangered Greater bamboo lemur Prolemur simus – Tony King, Christelle Chamberlan, Maholy Ravaloharimanitra & Tovonanahary Rasolofoharivelo
- Lowered sensitivity of bitter taste receptors to β-glucosides in bamboo lemurs: an instance of parallel and adaptive functional decline in TAS2R16? – Akihiro Itoigawa, Fabrizio Fierro, Morgan E. Chaney, M. Elise Lauterbur, Takashi Hayakawa6, Anthony J. Tosi, Masha Y. Niv and Hiroo Imai
- Greater bamboo lemur – Patricia C. Wright, Eileen Larney, Edward E Louis Jr, Rainer Dolch, Radoniana R. Rafaliarison
- Distribution of school reconstruction materials following Cyclone Giovanna to local communities working to conserve Greater bamboo lemurs in and around the Ankeniheny-Zahamena Corridor, eastern Madagascar – Christelle Chamberlan , Lovanirina Ranaivosoa , Maholy Ravaloharimanitra , H. Lucien Randrianarimanana , Hery N. T. Randriahaingo , Delphine Roullet , Tony King
- Coevolution of Cyanogenic Bamboos and Bamboo Lemurs on Madagascar – Daniel J Ballhorn, Fanny Patrika Rakotoarivelo, Stephanie Kaulz
- Feeding Ecology and Morphology Make a Bamboo Specialist Vulnerable to Climate Change – Stacey Tecot
- Arboreal camera trapping for the Critically Endangered Greater bamboo lemur Prolemur simus – Erik R Olson, Ryan A Marsch, Brittany N Bovard, H L Lucien Randrianarimanana, Maholy Ravaloharimanitra, Johah H Rasimbazafy and Tony King.
- Large-Culmed Bamboos in Madagascar: Distribution and FieldIdentification of the Primary Food Sources of the Critically Endangered Greater bamboo lemur Prolemur simus – King, Tony Randrianarimanana, H L Lucien, Rakotonirina, Laingoniaina HF, Mihaminekena, T Hasimija, Andrianandrasana, Z Anselmo et Al.
- Expanding Knowledge on Life History Traits and Infant Development in the Greater bamboo lemur (Prolemur simus): Contributions from Kianjavato, Madagascar – Cynthia L Frasier, Jean-Norbert Rakotonirina, Lamaherisolo Gervais Razanajatovo, Theoluc Stanislas Nasolonjanahary, Rasolonileniraka, Stephanson Bertin Mamiaritiana, Jean Fulbert Ramarolahy, Edward E. Louis
- Lemur Held Extinct Found on Madagascar – New York Times – The Associated Press, October 14, 1986
- High Energy or Protein Concentrations in Food as Possible Offsets for Cyanide Consumption by Specialized Bamboo Lemurs in Madagascar – Timothy M Eppley, Chia L. Tan, Summer J. Arrigo-Nelson, Giuseppe Donati
- Peeing poison: The biochemistry of bamboo lemur cyanide survival – M. Elise Lauterbur, Jeremy Peralta, Marta Concheiro-Guisan, Lydia Tongasoa, Liliana M Davalos, Patricia C Wright
Written by Sylvie Abrams, Mar 2022