Golden-crowned sifaka

Appearance

The golden-crowned sifaka is one of the smallest sifaka species with a weight of 3.4 to 3.6 kg , a head-body length of 45 to 47 cm , a tail length of 42 to 47 cm , and total length of 87 to 94 cm .Mittermeier et al. 2006, pp. 373–375. It is comparable in size to the sifakas inhabiting the southern and western dry forests, such as Coquerel's sifaka, the crowned sifaka, Von der Decken's sifaka, and Verreaux's sifaka. It has a coat of moderately long, creamy-white fur with a golden tint, dark black or chocolate-brown fur on its neck and throat, pale orange fur on the tops of its legs and forelimbs, a white tail and hindlimbs, and a characteristic bright orange-gold crown.Mittermeier et al. 2006, pp. 373–375. It is the only sifaka with prominent tufts of white fur protruding from its ears, making its head appear somewhat triangular and distinctive in appearance. Its eyes are orange, and its face is black and mostly hairless,Mittermeier et al. 2006, pp. 373–375. with dark gray-black fur with white hairs stretching from beneath the eyes to the cheeks. Its snout is blunt and rounded, and its broad nose helps to distinguish it from other sifakas. Occasionally the bridge of the nose will have a patch of white fur. Similar to other sifakas, this arboreal animal has long, strong legs that enable it to cling and leap between tree trunks and branches.Mittermeier et al. 2006, pp. 373–375.

Status

Because studies have shown that the golden-crowned sifaka are most likely to be found in large forest fragments ), the species is thought to be sensitive to forest fragmentation and degradation. However, since it has been found around gold mining camps and degraded forests, it is not restricted to undisturbed forests and appears to tolerate human activity. Regardless, with its low population, highly restricted range, and badly fragmented habitat, the prospect for survival for the golden-crowned sifaka is considered bleak. For these reasons, the International Union for Conservation of Nature added it to its list of the 25 most endangered primates in 1997. Previously, in 1992, the IUCN's Species Survival Commission Primate Specialist Group also assigned the species its highest priority rating. As of its 2008 assessment, the golden-crowned sifaka was downgraded from ''Critically Endangered'' to ''Endangered'' on the IUCN Red List. In its four previous assessments, it was listed as ''Critically Endangered'' in 1996 and 2000 and ''Endangered'' in 1990 and 1994.

The area inhabited by the golden-crowned sifaka is also an important agricultural and economical resource for the human population. Suggested conservation action aimed at protecting this species and its habitat has focused on offering varying degrees of protection to forest fragments in the region, allowing human activity and resource extraction in areas that have less conservation potential while strictly protecting areas critical to the species' survival. In 2002, none of the forested areas that the golden-crowned sifaka inhabits were part of a formally protected national park or reserve. A conservation study from 1989 called for the creation of a national park that includes the forest of Binara as well as the dry forests to the north of Daraina. A more recent study from 2002 proposed a network of protected forest areas including areas outside of the village of Daraina, forests north of the Monambato River, and the northern forests that constitute the species' northern reservoir. In 2005, Fanamby, a Malagasy non-governmental organization , teamed up with Conservation International to create a 20,000-hectare protected area that both Association Fanamby and the Ministry of Water and Forests manage.Mittermeier et al. 2006, pp. 373–375. As of 2008, only ten forest patches that could support viable populations remained, according to the IUCN.


Only one captive population of golden-crowned sifakas has been represented in a zoological collection. Building on a successful record of maintaining a viable captive Verreaux's sifaka population, the Duke Lemur Center in Durham, North Carolina, requested and obtained permission from the government of Madagascar to capture and export this unknown species for captive breeding. Plans were also made to establish a captive breeding program at the Ivoloina Forestry Station, now known as Parc Ivoloina. In November 1987, during the same expedition that resulted in the formal description of the species, two males and two females were caught and measured. Five others were also caught, but were released because they were juvenile males. In July 1988, a golden-crowned sifaka was born in captivity at the DLC. However, the captive population was small and not viable for long-term breeding, and captive sifakas have proven difficult to maintain due to their specialized dietary needs. The last captive individual died in 2008. Despite the loss of its small colony after 20 years, DLC believes that establishment of a captive population for conservation-oriented captive breeding purposes could provide an important second level of protection, particularly if habitat protection measures are unsuccessful.

Behavior

The golden-crowned sifaka is primarily active during the day , but researchers have witnessed activity in the early morning and evening during the rainy season .Mittermeier et al. 2006, pp. 373–375. In captivity, it has been observed feeding at night, unlike captive Verreaux's sifakas. It travels between 461.7 and 1,077 m per day, an intermediate range compared to other sifakas of the eastern forests. The golden-crowned sifaka can be observed feeding and resting higher in the canopy during the dry season . It sleeps in the taller trees of the forest at night.

When stressed, the golden-crowned sifaka emits grunting vocalizations as well as repeated "''churrs''" that escalate into a high-amplitude "''whinney''." Its ground predator alarm call, which sounds like "''shē-fäk''", closely resembles that of Verreaux's sifaka. It also emits mobbing alarm calls in response to birds of prey.The social structure of the golden-crowned sifaka is very similar to that of Verreaux's sifaka, both averaging between five and six individuals per group, with a range between three to ten. Unlike the Verreaux's sifaka, group sex ratios are more evenly balanced, consisting of two or more members of both sexes. Females are dominant within the group, and only one female breeds successfully each season. Males will roam between groups during the mating season.

Because of their smaller home ranges relative to other sifakas, group encounters are slightly more common, occurring a few times a month. It has been noted that the temperament of the golden-crowned sifaka is more volatile than that of other sifaka species and, in the case of a dispute, this animal frequently emits a grunt-like vocalization that seems to signal annoyance. Aggressive interactions between groups are generally non-physical but include loud growling, territorial marking, chasing, and ritualistic leaping displays. Same-sexed individuals act most aggressively towards each other during such encounters. Scent marking is the most common form of territorial defense, with scent marks acting as "signposts" to demarcate territorial boundaries. Females use glands in the genital regions while males use both anogenital and chest glands.

Habitat

The golden-crowned sifaka lives in dry deciduous, gallery, and semi-evergreen forests and is found at altitudes up to 500 m , though it seems to prefer lower elevations. Surveys have shown it to be limited to highly fragmented forests surrounding the town of Daraina in an area encircled by the Loky and Manambato rivers in northeastern Madagascar. The golden-crowned sifaka has one of the smallest geographic ranges of all indriid lemur species.Mittermeier et al. 2006, pp. 373–375. Out of 75 forest fragments studied by researchers, its presence could be definitively reported in only 44, totaling 44,125 ha . This study, published in 2002, also estimated the total species population and observed population densities. Home range size varied between 0.18 and 0.29 km2 per group. With an average group size of five individuals, the population density ranged between 17 and 28 individuals per km2. Another home range size estimate of 0.09 to 0.12 km2 has also been suggested with a population density range of 10 and 23 individuals per km2.Mittermeier et al. 2006, pp. 373–375. The forested area available to the species within its desired elevation range was estimated at 360 km2 , yielding an estimated population of 6,120–10,080 and a breeding population between 2,520 and 3,960 individuals. However, a study published in 2010 using line transect data from 2006 and 2008 in five major forest fragments yielded an estimated population of 18,000 individuals.

The species is sympatric with two other medium-sized lemurs: the Sanford's brown lemur and the crowned lemur .Mittermeier et al. 2006, pp. 270–271.

Reproduction

The golden-crowned sifaka is a seasonal breeder, often mating during the last week of January.Mittermeier et al. 2006, pp. 373–375. Its gestation period is a little less than six months, and its lactation period is five months. Research has indicated that reproduction is strategically linked with forest seasonality. Gestation starts in the later part of the wet season , and continues for approximately 170 days. Parturition occurs in the middle of the dry season .Mittermeier et al. 2006, pp. 373–375. Weaning occurs during the middle of the wet season, in December, when an abundance of immature leaves is available.Mittermeier et al. 2006, pp. 373–375. It is thought that such reproductive timing exists to ensure adequate protein intake from the immature leaves for both mother and child at the end of the lactation period.

Females reproduce once every two years. Infants are born with little hair and initially cling to their mother's belly. As they mature, they begin to ride on her back. Following weaning, riding on the back is only tolerated for short durations, particularly when the group is alerted to the presence of a predator. By one year of age, the juveniles are 70% of their full adult body weight. Infant mortality is high in this species. Upon reaching sexual maturity, males leave their natal group and transfer to neighboring social groups. Observations by researchers and reports from local people indicate that this species will jump to the ground and cross more than 200 m of grassland to reach nearby forest patches. This suggests that forest fragmentation may not completely isolate separated populations.

Food

The diet of the golden-crowned sifaka consists of a wide variety of plants—as many as 80 species—whose availability varies based on the season. It is a seed predator, making seeds a year-round staple in its diet when available. The golden-crowned sifaka also eats unripe fruits, flowers, and leaves. One study showed a diet composition of 37% unripe fruit and seeds, 22% immature leaves, 17% mature leaves, 13% flowers, and 9% fruit pulp. Individuals have also been observed consuming tree bark during the dry season.Mittermeier et al. 2006, pp. 373–375. In general, approximately 60% of its diet consists of unripe fruits and seed, mainly from leguminous pods, and less than 50% consists of leaves. At Daraina, it has been observed feeding on the sakoa tree and on mango trees. Immature leaves and flowers are eaten when available, in the early wet season. Daily traveling distance tends to increase when immature leaves are available. Studies have also shown that when food distribution is patchy, feeding times are shorter and more time is spent traveling. Dietary diversity has been shown to be consistent between populations, suggesting that it is important for the lemur to get a varied mix of nutrients and to protect itself from high levels of specific plant toxins.

A study in 1993 showed variability and flexibility in feeding preferences between three research sites around Daraina. Plant species preferences changed between wetter, intermediate, and drier forests:

Predators

The only predator known to target this species is the fossa, although the golden-crowned sifaka reacts to the presence of birds of prey with alarm calls. A hematology and serum chemistry study published in 1995 revealed that 59% of the wild golden-crowned sifakas sampled were infected with a microfilarial parasite, a potentially unknown species of nematode in the genus ''Mansonella''. Healthy, infected individuals did not appear to be adversely affected by the infestation, but the overall effect on the dwindling population is unknown. Also, no malarial or intestinal parasites were found, although 48% of the golden-crowned sifakas examined had external ear mites.