Diadem Sifaka

The diademed sifaka is one of the world's largest living lemurs, with a total adult length of @ 105 cm (41 in),[3] half of which is tail. It weighs 5-7 kg. Sifakas reach lengths of 45-55 cm, with the tail adding 43-56 cm. Its coat is moderately long, silky and luxuriant. It has long powerful legs and grasping hands and feet, enabling it to leap from one vertical trunk to another. It has a white head, grey shoulders, tail, and back and golden limbs. Russell Mittermeier says it is "one of the most colorful and attractive of all the lemurs" [4]. The diademed sifaka has a white head with a dark crown; the rest of the body varies in shades of grey except for the rich golden-orange of the arms and legs, and the black hands, feet and face (4). The long white fur encircling the muzzle and covering the cheeks, forehead and chin and the dark crown engenders the "diadem" or crown appearance. The eyes are reddish-brown, the muzzle is short and the darkish gray to jet black face is bare. The black crown fur often extends to the nape of the neck. The upper back and shoulder fur are slate grayish, but the lower back is lighter in colour attaining a silvery quality. The flanks and tail are paler gray, sometimes white, as is the ventral fur. The hands and feet are black; the arms, legs and tail base are yellowish-golden or rich golden-orange. Only the male has a large cutaneous gland at the exterior center of the throat; this is darkish gray to jet black.

The diademed sifaka is one of the mostly widely distributed sifakas [5]. It occurs in primary rainforests and smaller forest fragments at altitudes of 200-800 m throughout much of the eastern Madagascar lowland forests and at altitudes 800- 1,625 m in subhumid montane rainforests. The range extends to at least the Mananara Nord River in the north to the Onive and Mongoro Rivers in the south (11,12). The range is situated between those of the Milne-Edward's and silky sifakas (12). Earlier authors said it occurred between Antainambalana River near Maroantsetra and Mananara Nord River (13). Members of an anomalous outlier population of P. diadema in south central Madagascar show various colour markings, including an all black lemur. DNA analyses have not concluded if this group constitutes a new species.There is a clinal variation between P. diadema and P. edwardsi in the extreme southern portion of the range [6]. Specific locations for sighting the diademed sifaka are Mantadia National Park and in the forests of Tsinjoarivo.[7]

It lives in multi-male/multi-female groups of 2-10 individuals (4). Communication is rich and varied. The sifakas use scent-marking to defend home ranges of 20-50 ha (14). Males scent mark twice as often as females. Scent marking frequency doubles when approaching the territorial boundaries (10,15-17). Vocalizations are used mainly to maintain vocal and chemical communication. Sifakas use tactile communication, in the form of grooming, play, and aggression. This may be very important between mothers and their young, as well as between mates. Sifakas probably use facial expressions, body postures and other visual signals in their communication (18). The sifaka defends the group's territory strongly against other diademed sifakas, but shares territory with red-bellied and common brown lemur. It is thought to traverse the greatest daily path distance relative to other members of its family in its patrolling and foraging, attaining a typical travel distance in excess of 1.6 km a day.

It is thought that the diademed sifaka behaves like the related Milne-Edward's sifaka (2). The sifaka is diurnal and spends almost all its time in trees, being rarely seen on the ground; it is a vertical clinger and lateral leaper through the trees (2). It can achieve lateral aerial propulsion of up to 30 km per hour, due to muscular leg thrusting action pushing off from a vertical tree trunk. Individuals may alight on the ground to search for fallen fruit and to engage in play-fighting; some sifakas eat soil, possibly in an effort to rid themselves of toxins (4).

It is herbivorous, eating mainly verdant leaves, as well as flowers, seeds, fruits, and young shoots from @ 25 species of plants (2) at all levels of the canopy. As a frugivore, it probably helps to disperse seeds. As potential prey items, Individuals of all ages and both sexes may impact predator populations. are subject to predation. Suspected avian predators include Madagascar harrier-hawks and Henst's goshawks. The fossa is an ambush predator. The sifaka gives 2 alarm vocalizations in response to predators. The ground predator call is a "tzisk-tzisk-tzisk" or "kiss-sneeze" when a fossa, Nile crocodile or another terrestrial predator is perceived [8]. The aerial predator call is a "honk-honk-honk" (10,15-17). The sifaka high levels of activity is linked to a diet high in energy content, including a high consumption of two plants containing high concentrations of alkaloids.

Mating occurs between resident males and resident females, with no recorded cases of invading males successfully copulating. The female is probably receptive to mating few days per year. Being dominant, she has the greatest input to mate selection. There is a hierarchy system for mating; it seems that only the dominant male copulates with the females. Submissive males may show aggression and try to keep the dominant male from mating. Copulation occurs in summer (in December and January) and there is usually one offspring per female every 2 years. Gestation period is @ 157-180 days. Births for Milne-Edward's sifaka occur in May and July, but those for other species may occur later in the year (4). Females can produce 1-2 offspring in winter (May-July) every 2 years (10,16). The altricial newborn young weighs @ 145 g. The infant initially clings to its mothers belly before transferring to her back after a month (4). Nursing begins to decrease from the age of 2 months. At 1 year old, suckling during the day ceases. As well as continue until the infant is two years old. In addition to food, the mother provides her young with protection, grooming, and socialization. When the young is 2 years old, its mother's milk does not provide it with a substantial amount of their nutrition. Sexual maturity is reached at 4 years for females and 5 years for males. Sexual maturity is reached at 2-5 years of age; the male matures more slowly than the female. Males disperse, but females stay within their natal group and are the dominant sex in the group (4). Captive sifakas may live beyond 23 years in captivity (18). A wild sifaka may live up to 21 years with no signs of reproductive senescence except a slight increase in mortality with age (19). Dental senescence may occur described in animals over 18 years old. Wild sifakas may be able to live over 27 years in the wild (20).

The diademed sifaka is classified as Critically Endangered on the IUCN Red List and is listed on Appendix I of CITES. In 2002, population estimates for the species ranged from 6,000-10,000 individuals [9]. The primary threat is habitat reduction due to shifting cultivation by native peoples. This threat is also present within designated national parks, where it is hard for the government to enforce national laws protecting habitat. Pressures of overpopulation in central and eastern Madagascar cause many of the rural poor to seek subsistence by seizing forest lands, timber extraction and undertaking slash-and-burn tactics as their initial step in a shifting cultivation system (4). Deliberate fires encroach on the highly- fragmented habitat (4). Returns from such land use are usually meagre, yielding small amounts of charcoal, firewood or grass crop for grazing of zebu (4). Illegal rum production, involving planting sugar cane fields threatens populations in Tsinjoarivo. The species is thought to have undergone a reduction of more than 50% over the past 30 years due primarily to a decline in area and quality of habitat within its range of the species and due to levels of exploitation; the population trend is 'Decreasing'. It is hunted for food, even in protected areas (14). This species occurs in three national parks (Mananara-Nord, Mantadia, and Zahamena), two strict nature reserves (Betampona and Zahamena), and three special reserves (Ambatovaky, Mangerivola, and Marotandrano) (14). Additional populations have been identified in the Andriantantely Classified Forest, Tsinjoarivo Classified Forest, the Marokitay Forest Reserve, and in the unprotected forests of Anosibe, Anjozorobe, Didy, Iofa, Maromiza and Sandranantitra (14). The Tsinjoarivo Classified Forest has already been recommended as a new protected area. In response to threats, several reserves have been established within the last few decades, along with campaigns to educate locals and find better methods of agriculture (10,17,21). This species and other unique plants and animals have stimulated a large amount of ecotourism, helping to bolster the economy of a severely depressed nation (21). This species was represented in a zoological collection at the Duke University Primate Center in Durham, North Carolina, USA.

The diademed sifaka comprised 4 distinct subspecies, which are now classified as separate species (4) and form a tight species group within the Propithecus genus, but all have a distinct range (10). The other 4 species are the Milne-Edwards' sifaka (P. edwardsi), Perrier's sifaka (P. perrieri), golden-crowned sifaka, (P. tattersalli) and silky sifaka (P. candidus). They have luxuriant silky coats and are powerful leapers. They share similar characteristics of gestation length (4 months), age of sexual maturity, female dominance, life expectancy (18 years) and propensity for sunbathing while stretched out on a branch. They differ in colouration and markings, but have black, naked faces and red-orange eyes.