Geographic Distribution and Habitat
Like all lemurs, the diademed sifakas (Propithecus diadema) are endemic to Madagascar and live in the eastern and northeastern rainforests of the island, at altitudes between 2,260 and 5,000 ft (800-1500 m). It is thought to be one of the most widely distributed of the sifaka species.
Size, Weight, and Lifespan
Diademed sifakas are large lemurs, the smallest of them being the subset group found in the Tsinjoarivo region. Females are slightly larger than males. Males weigh between 7 and 14 lb (3-6.5 kg), while females weigh between 7 and 15 lb (3-6.7 kg). Males measure 14 to 19 in (37-50 cm) in length, while females range from 14 to 20 in (37-53 cm).
These sifakas may have a maximum lifespan of 25-30 years, although they are usually killed by predators and rarely live beyond 10 or 12 years.
Diademed sifakas’ bodies are covered in long silky hair that is reddish on their limbs and black and gray on their bodies and heads, with a patch of white hair that draws a line across their forehead. This crown-like feature is why they are referred to as “diademed” sifakas.
They have a small head, a black face with a snout, razor-sharp canines, and a tooth comb at the front of the lower mandible to clean and remove mats from their fur. They are diurnal creatures—their big round orange eyes are leftover from their nocturnal ancestors.
Their long legs are strong and perfectly adapted to vertical climbing and leaping. Their hands and feet (which are furry on top) have an opposable thumb/toe and long skinny fingers with nails. The skin of the palms of their hands and the soles of their feet is bare and has ridges—just like a human’s. The second toe of their feet has a toilet claw, which they use to clean their fur. Their bushy tail is pretty much the size of their body and helps them keep their balance while in the canopy.
What Does It Mean?
Adorned as if with a diadem (bejeweled headband).
Active during daylight hours.
A specialized grooming claw common to prosimians and certain other primates.
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Diademed sifakas are mostly folivorous and feed on at least 100 different identified plant species. Not much is known yet of their digestive system, but they do have large salivary glands. It is thought that these large glands may deactivate tannins with compounds in their saliva. In normal conditions, diademed sifakas spend half of their feeding time on immature leaves and a quarter on fruit. Even so, leaves are their least favorite food item on the menu; they much prefer fruit, seeds, buds, and flowers. They also consume soil, galls (a growth on the external tissues of plants), leafstalks, bark, insects, and anything else that might strike their fancy. There is no conclusion yet as to why they occasionally ingest soil, but there are some theories: it may help detoxify plant toxins or tannins; it may supplement their diet with trace minerals; and it may help them fend off parasites.
During the rainy season (from November to March), fruit is abundant and sifakas living in continuous forested areas get about 70 percent of their food foraging in three tree species (Ocotea, Erythroxylum, and Maintipototra). Between June and October (in the early to late dry season), leaves become their main food source.
Time spent foraging varies greatly between groups living in fragmented forest compared to continuous forest. The former spend 30-40% of their time feeding on mistletoe, as opposed to 28-30% for the latter. It is also important to note that in fragmented forests, individuals feed on multiple patches and dominant individuals usually feed on the best patches, so it is probable that lower-ranking individuals get less nutrients in fragmented forest than they would get in continuous forest. Studies indicate that similarly aged immature sifakas weigh less in fragmented forest than in continuous forest.
Mistletoe is a year-long staple and groups living in fragmented forests heavily rely on it—except in January when they are able to find seeds from fruiting tree species like Macaranga ankafinensis.
Primates usually forage for food using sight, by spotting ripe fruit and memorizing those locations. Diademed sifakas also rely on olfactory senses, specifically to find Langsdorffia and Cytinus. These plants grow on the roots of trees and vines. They only emerge from the ground when mature and have a strong sweet smell when split open. Between the months of July and October, hungry sifakas descend from the trees, walk slowly while sniffing the ground left and right, and dig and overturn leaves until they find the delicacy they are looking for. Foraging sifakas are totally focused on their task, not even bothering to play; since cases of aggressive behavior and theft have been observed during the search for some shoots and roots, this likely indicates that they are prized food items.
Sifakas are also unique compared to other primates because during the lean season, instead of traveling longer distances, spending more time foraging and eating more, they travel less, spend less time foraging, and eat less food. Why they do this is not well understood. It could be that preferred food items are easy to pick, easy to ingest, easy to digest, and provide good nutrition, whereas fallback foods like mistletoe, although abundant, provide fewer calories and little nutritional gain, are harder to digest, and therefore require more energy.
Behavior and Lifestyle
Diademed sifakas are diurnal and use multiple layers of the forest; they spend time up in the canopy but also spend time on the ground to forage and socialize.
They remain upright and, propelled by the power of their hind legs, can leap distances up to 30 ft (9 m) from tree to tree. When moving on the ground, they hop sideways on their hind legs.
Daily Life and Group Dynamics
Groups vary in size from three to nine individuals, with one adult male, one or two adult females, subadults, and infants. These are usually stable and remain together for several years.
Groups may split up for a few days while foraging, but tend to remain within 300 ft (100 m) of each other. They forage during the day and because females are dominant, it is not unusual to see them push males away at feeding sites. Once satiated, everyone in the group retires to their sleeping site at sunset. They use many sleeping sites within their home range. They curl up, huddling with one or two other individuals on a comfortable branch and sleep from 3 pm to 8 am in the dry season and from 6 pm to 5 am in the rainy season.
Scent marking plays an important role in the social life of sifakas. It is used to mark territory, attract the opposite sex, and, for males, to claim ownership over a female. Males have been observed scent marking twice as many times as females. Both genders have anogenital scent glands, but only males have a large scent gland on their throat.
The Malagasy name for the diademed sifaka is “simpona,” but in areas around Tsinjoarivo it is called “sadabe.”
Queen Ranavalona II (1829-1883) was ahead of her time. Concerned about deforestation, she banned the practice of “tavy” (slash and burn agriculture), charcoal making, and the building of houses in the forest.
Like all other primates, diademed sifakas communicate in many ways. Vocalizations keep the group together. They use contact calls, a lost call, and three alarm calls. These are specific to various threats, for instance the “honk-honk-honk” call is only used for aerial predators. Anecdotally, the word “sifaka” is derived from the unusual sound—“shi-fakh”—that they utter in presence of ground predators.
Scent marking is another common way to communicate with members of the troop, and those outside the troop. Scent marking increases at the edge of the group territory. Grooming is also extremely important between mothers and their offspring and between mates. It is also a way to bond with other members of the group. They groom using their tooth comb.
Body posture, eye movement, and leaping patterns are other ways to convey messages. During territorial competition, for example, the members of each troop leap toward an undefended part of a tree. Individuals of both troops move in formations, while scent marking, staring at one another, and growling. It is worth mentioning that inter-group encounters are rare and do not normally result in physical fights because scent marking is a very effective way to keep intruders at bay.
Reproduction and Family
Each group is composed of one breeding adult and one or two adult females. Breeding is linked to food availability and is therefore limited in time to when food is most abundant. Females are dominant over males and remain in their native groups, while males migrate to a different group at age 4 to 6 when they reach sexual maturity. Females become sexually active at 4 years old, but they are more fertile at age 6.
Males who are dominant over other males are better at wooing the ladies, but they have a short window of time to do so. Indeed, females are only fertile for 24 hours. Fortunately for the males, not all females are fertile on the same day.
Females give birth to one offspring between the months of June and July, after a gestation period of approximately six months. Twins are extremely rare. Once they have given birth, females are not fertile again for another two years.
The babies are born white and cling to their mother’s belly for the first month of life, then they hang on her back. The mother’s milk is the only food they get for two months, then they gradually start eating other foods but may continue suckling until the age of 2. They also rely on their mother for protection and grooming.
Infant mortality is low. Diademed sifaka mothers are very attentive. When a mother and daughter breed simultaneously, they help each other with their infants. This is the only case in which females would help each other rearing offspring. Males are not involved—some don’t even want to be touched by infants.
Although it is thought that, like other primates, diademed sifaka males might kill infants to ensure their lineage, no direct observations of this behavior have been made.
Diademed sikafas play an important role in seed dispersal of fruiting and non-fruiting tree species. They also provide food for various predators, such as the Madagascar harrier-hawks, the Henst’s goshawks, and fossas.
Conservation Status and Threats
Madagascar is unique for its biodiversity. Eighty percent of the 200,000 known species on the island do not exist anywhere else. That includes the Critically Endangered diademed sifakas, per the International Union for Conservation of Nature (IUCN, 2018).
Not only do they face daily threats from fierce predators, such as the fossa, but they also face the threat of human activity. Deforestation has been changing the landscape of the island for decades. Between 1950 and 2000, 40% of the forest cover disappeared. Deforestation is due to human population growth, extreme wild fires, and “tavy,” or slash-and-burn agriculture, which farmers resort to so they can feed their families. This practice consists of burning an acre or two of the forest to plant rice. After a couple years of production, the land is left uncultivated for up to 6 years, then the process is repeated. Slash and burn increases erosion, can contaminate water, reduces soil fertility, and changes the landscape. As the soil becomes depleted of nutrients, scrub vegetation grows and alien grasses may invade the land as well.
Forests are also being cut for charcoal production. The major issue in eastern Madagascar, where diademed sifakas live, is timber extraction for precious hardwoods like ebony and rosewood.
In fragmented forests, diademed sifakas are even more vulnerable to predators. Because nutrient-rich food is not readily available, their protein intake is lower than in continuous forest. They also have lower levels of manganese, zinc, and iron. Poor nutrition leads to lower fertility; more stress leads to a compromised immune system, which makes these sifakas more vulnerable to diseases as well. Group cohesion is affected and “lost calls” from the sifakas occur more regularly in groups living in fragmented forest than in continuous forest.
Some areas in Madagascar are placed under protection, like the primary forest of Maromizaha, east of Antananarivo, which is managed by GERP (Groupe d’Etude et de Recherche sur les Primates de Madagascar).
The Duke Lemur Center has been working closely with the Madagascar Fauna and Flora Group (MFG), a consortium of zoos and other institutions dedicated to conservation, on non-invasive studies of diademed sifakas at Betampona, a protected forest. Thanks to these organizations, Betampona is protected from illegal wood cutting and wildlife poaching.
No conservation efforts can be effective if they don’t include the people who live and share their environment with wildlife. This is why several local and international organizations and research institutions implement programs with a focus on awareness and education. For the past fifteen years, the Sadabe research teams, for example, have been visiting local schools to share information about their project, bring children into the forest to see groups of sifaka, and teach them about conservation and biodiversity. In the words of Dr. Mitchell Irwin, who leads the Sadabe team: “Everyone should come and visit the diademed sifakas.”
Special thanks to Dr. Mitchell Irwin, PhD, Associate Professor Dept. of Anthropology, Northern Illinois University for his guidance during the development of this profile. Dr. Irwin is a biological anthropologist specializing in primate ecology and behavior. His research focuses on the ecological adaptations of Madagascar’s lemurs and how habitat disturbance affects the ecology, behavior, and health of individuals and populations.
And thanks to Sara Clark, Director of Communications, Guest Experience Manager, Duke Lemur Center for providing photos of and information about Romeo, his life, and what was learned from his captivity. Romeo was the only diademed sifaka in captivity and lived at their facility until 2012. Romeo provided insight into diademed sifaka intelligence and learning abilities.
- www.national geographic.com/animals/mammals/group/sifakas
- American Journal of Primatology 69:471-476 (2007) – “Diademed Sifakas (Propithecus diadema) Use Olfaction to Forage for the Inflorescences of Subterranean Parasitic Plants (Balanophoraceae: Langsdorffia sp., and Cytinaceae: Cytinus sp.)” – Mitchell T. Irwin, Fanomezantsoa Jean-Luc Raharison, Harison Rakatoarimanana, Edmond Razanadrakoto, Edmond Ranaivoson, Justin Rakotofanala, Charles Randrianarimanana.
- American Journal of Primatology 69:434-447 (2007) – “Living in Forest Fragments Reduces Group Cohesion in Diademed Sifakas (Propithecus diadema) in Eastern Madagascar by Reducing Food Patch Size.” – Mitchell T. Irwin
- International Journal of Primatology (2008) 29.95-115 – ‘Feeding Ecology of Propithecus diadema in Forest Fragments and Continuous Forest” – Mitchell T. Irwin
- Animal Conservation. Print ISSN 1367-9430 – “Spatial and temporal variability in predation on rainforest primates: do forest fragmentation and prediction act synergistically?” – Mitchell T. Irwin, J-L Raharison, P. C. Wright.
- American Journal of Primatology 72:1013-1025 (2010) – “Variation in Physiological Health of Diademed Sifakas Across Intact and Fragmented Forest at Tsinjoarivo, Eastern Madagascar” – Mitchell T. Irwin, Randall E. Junge, Jean-Luc Raharison, Karen E. Samonds.
- American Journal of Physical Anthropology 153:78-91 (2014) – “Nutritional Correlates of the “Lean Season”: Effects of Seasonality and Frugivory on the Nutritional Ecology of Diademed Sifakas” – Mitchell T. Irwin, Jean-Luc Raharison, David Raubenheimer, Colin A. Chapman, Jessica M.Rothman.
- IUCN – Lemurs of Madagascar – A Strategy for their Conservation 2013-2016.
- NASA – Land Cover / Land-Use Change Program – “Deforestation in Madagascar” https://www.lcluc.umd.edu/content/global-map-hotspots-land-cover-and-land-use-change
- IUCN Red List of endangered species.
- CITES – Appendix I
Written by Sylvie Abrams, September 2018