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Golden-crowned sifaka

Jul 29, 2014

The golden-crowned sifaka or Tattersall's sifaka is a medium-sized lemur characterized by mostly white fur, prominent furry ears, and a golden-orange crown. It is one of the smallest sifakas, weighing around 3.5 kg (7.7 lb) and measuring approximately 90 cm (35 in) from head to tail. Like all sifakas, it is a vertical clinger and leaper, and its diet includes mostly seeds and leaves. The golden-crowned sifaka is named after its discoverer, Ian Tattersall, who first spotted the species in 1974. However, it was not formally described until 1988, after a research team led by Elwyn Simons observed and captured some specimens for captive breeding.

Found in gallery, deciduous, and semi-evergreen forest, its restricted range includes 44 forest fragments, totaling an area of 44,125 hectares (109,040 acres; 170.37 sq mi), centered around the town of Daraina in northeast Madagascar. Its estimated population is between 6,000 and 10,000 individuals. It is primarily active during the day, although it also tends to be active at dawn and dusk during the rainy season. It sleeps in tall emergent trees and is preyed upon by the fossa. The golden-crowned sifaka lives in groups of around five to six individuals, containing a balanced number of adult males and females. Scent is used to mark territories, which are defended by growling, chasing, and ritualistic leaping displays. Reproduction is seasonal, with gestation lasting six months and lactation lasting five months. Infants are weaned during the wet season to ensure the best chances of survival.

The small range and fragmented populations of this species weigh heavily on its survival. Forest fragmentation, habitat destruction, poaching, slash-and-burn agriculture, and other human factors threaten its existence. The golden-crowned sifaka is listed by the IUCN Red List as Endangered. Its range was originally not covered by any national parks or protected areas in Madagascar, but a new protected area was established in 2005 to include a 20,000 ha (49,000 acres; 77 sq mi) portion. Attempts have been made to keep the golden-crowned sifaka in captivity at the Duke Lemur Center in Durham, North Carolina. The small colony was maintained from 1988 to 2008. In Madagascar, lawlessness resulting from the 2009 political coup led to increased poaching of this species, and many were sold to local restaurants as a delicacy.

Taxonomy

The golden-crowned or Tattersall's sifaka, known locally as ankomba malandy (or akomba malandy, meaning "white lemur"), was discovered in 1974 north of Vohemar in northeast Madagascar by Ian Tattersall, who observed but did not capture the animal. Unsure of its classification, Tattersall provisionally considered it a variant of the silky sifaka in his 1982 book, The Primates of Madagascar, citing its mostly off-white to yellowish fur, but also noting its uncharacteristic orange crown patch and tufted ears. Driven by a report in 1986 that the forest where Tattersall had observed this unique sifaka was contracted to be clear-cut for charcoal production, a research team from the Duke Lemur Center, led by Elwyn Simons, obtained permits to capture specimens for a captive breeding program. Simons and his team were the first to capture and observe the golden-crowned sifaka, formally describing it as a new species in 1988 and naming it in honor of Tattersall. The specimens were found 6 to 7 km (3.7 to 4.3 mi) northeast of Daraina, a village in the northeast corner of Madagascar.

There have been conflicting studies regarding the taxonomic status of the golden-crowned sifaka. When described by Simons in 1988, size, vocalizations, and karyotypes (the number and appearance of chromosomes) were compared with the other sifakas. In terms of size, general morphology, and vocalizations, the golden-crowned sifaka is more comparable to the western forest sifakas in that it is smaller in length and weight. Its karyotype, however, is more similar to that of the eastern forest sifakas.

Anatomy and physiology

The golden-crowned sifaka is one of the smallest sifaka species with a weight of 3.4 to 3.6 kg (7.5 to 7.9 lb), a head-body length of 45 to 47 cm (18 to 19 in), a tail length of 42 to 47 cm (17 to 19 in), and total length of 87 to 94 cm (34 to 37 in). 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. 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, 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.

Geographic range and habitat

The geographic range of the crowned lemur overlaps the range of the golden-crowned sifaka.
The golden-crowned sifaka lives in dry deciduous, gallery, and semi-evergreen forests and is found at altitudes up to 500 m (1,640 ft), 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. Out of 75 forest fragments studied by researchers, its presence could be definitively reported in only 44, totaling 44,125 ha (109,040 acres; 170.37 sq mi). 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 (0.069 and 0.112 sq mi) per group. With an average group size of five individuals, the population density ranged between 17 and 28 individuals per km2. The forested area available to the species within its desired elevation range was estimated at 360 km2 (140 sq mi), yielding an estimated population of 6,120–10,080 and a breeding population between 2,520 and 3,960 individuals. In 2006 and 2008 Quéméré et al. conducted line transect distance sampling in 5 of the main forest fragment of its distribution range yielding an updated estimate of the population size of ~18,000 individuals.

The species is sympatric (coexists) with two other medium-sized lemurs: the Sanford's brown lemur and the crowned lemur.

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 (November through April). In captivity, it has been observed feeding at night, unlike captive Verreaux's sifakas. It travels between 461.7 and 1,077 m (1,515 and 3,533 ft) 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 (May through October). It sleeps in the taller trees (the emergent layer) 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.

Social organization

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 ("anogenital") while males use both anogenital and chest glands.