Шелковистый сифаки (индри). Хохлатые индри, сифаки, пропитеки. Propithecus candidus. Propithecus Bennett, 1832 = Хохлатые индри, сифаки, пропитеки

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Propithecus candidus = Шелковистый сифаки

Фото

Вид: Propithecus candidus = Шелковистый сифаки

Propithecus candidus= SILKY SIFAKA

Total length: 930-1,050mm. Head/body length: 480-540mm. Tail lengtФотоh: 450-510mm. Weight: 5 - 6.5 kg.

The pelage is long, silky and uniformly creamy-white in colour. Some individuals have tints of silver-grey around the crown, back and limbs. The pygal area around the lower back and base of the tail may also be darker and slightly discoloured. The face is bare and slate-grey black, while the eyes are deep orange-red. Some individuals seen in the Anjanaharibe-Sud and Marojejy Massifs seem to lack skin pigment on their faces and other areas to a varying extent. These areas appear either totally pink or a mixture of pink and slate-grey.

The Silky Sifaka is large, vertically clinging and leaping lemur with very distinctive all-white coloration and cannot be mistaken for any other lemur within its range.

Unlike P. perrieri and P. edwardsi where adult males and females are difficult to distinguish, male and female P. candidus and P. diadema can be readily distinguished from one another in that they differ in the pelage coloration of their uppФото er ventral torso. Silky sifaka adult males possess a large brown “chest patch” that results from chest scent marking with the sternal-gular gland. As rates of male chest scent marking increase during the mating season, male chest patches become far larger in size and can cover the entire front torso to the abdomen (Patel 2006).

HabitaT & Distribution

P. candidus occurs in primary mid-altitude and montane rainforest. Elevations above 700m are preferred and it has been observed up to approximately 1,600m (Safford and Duckworth 1990; Sterling and McFadden 2000). The Silky Sifaka is only found at the extreme northern end of the eastern rainforest belt. Its range extends from Marojejy Massif in the north, around the Andapa Basin to Anjanaharibe-Sud and then south possibly to the region of Ambodivoahangy. This range covers an area of no more than 2,250km2.

CONSERVATION THREATS

The silky sifaka is new species of primate (Mayor et al. 2004), one of the three most critically endangered primates in Madagascar, and one of the top 25 most critically endangered primates out of over 620 total primate taxa (Mittermeier et al. 2005b).

Historically, as in other lemurs, the greatest conservation threat to the silky sifaka has been cultivation of hill rice through slash-and-burn agriculture or ‘tavy’ (Mittermeier et al. 1994). Although human hunting of primates in Madagascar is generally less widespread than in Africa or Asia (Cowlishaw and Dunbar 2000), nevertheless in some parts of Madagascar, such as Marojejy National Park, steady lemur poaching is evident. Tattersall (1982) suggested hunting must be occurring given that the most accessible parts of Marojejy seemed “largely bereft of larger mammals and birds”. Duckworth et al. (1995) found numerous lemur traps and “villagers said that lemur hunting is their main reason for penetrating the reserve” p.556. More recently, Goodman (2000) identified many human trails utilized by local people during lemur hunting, to gain access to hidden agriculture, and harvest forest plants for medicinal and construction purposes. In 2000, a silky sifaka was killed by poacher, but confiscated by local authorities (see photo). Similarly, during 14.5 months of research from 2001 to 2003, several episodes of lemur poaching within “protected areas” were evident. Estimated lemurs killed per hunt ranged from several to 70 with each being sold for 25,000 FMG ($4 USD) on average (Patel et al. 2005c). Most recently, in 2005 two silky sifakas along with 16 White-fronted brown lemurs were killed with guns by local hunters, but again confiscated by local authorities. As is typical, the hunters received virtually no punishment.

Unfortunately, there is no fady or taboo against hunting of the silky sifaka as there is against hunting of Indri, the largest extant lemur. Nor is there a shortage of meat in this cattle and rice culture situated within the wealthy vanilla growing region of Madagascar. After questioning numerous local villagers and authorities as to the reason for lemur hunting, it became clear that upper middle class families enjoyed the taste of wild lemur as a delicacy or “picnic food”. Several individuals remarked that the meat tastes so good, one does not even need sakai or Malagasy hot sauce. Several individuals testified that the upper middle class will hire local more impoverished men and provide them with guns and bullets for the lemur hunt (Patel et al. 2005c).

Behavior

Studies of this species are in their infancy, although there has been one intensive 14.5 month study (Patel 2003b) as well as several short-term studies (Kelly and Mayor 2002, Mayor et al. 2004). The silky sifaka is diurnal and lives in multi-male/multi-female groups of between two and nine individuals (Duckworth et al 1995). Smaller groups of three to four probably consist of an adult pair plus their offspring, while larger groups probably constitute mutually familiar foraging units that may contain more than one breeding pair together with juveniles. The large group at Camp 2 of Marojejy has a home range size of 44 ha, and travels on average 710m per day ascending up to 525m asl (above sea level) in a single day (Santorelli et al. 2006). During travel, males in this group were significantly more likely to be last in travel order than females who were significantly more likely to be first in travel .

Activity begins at dawn when the group moves off to begin foraging, although in periods of poor weather this is often delayed. Activity budget, calculated from continuous random focal samples, revealed that these folivorous seed-predators spend most of their time resting (45%) and foraging (22%), though (predominantly affiliative) social behavior was abundant (16%). The activity budget differed between adult males and females (chi-squared test of independence, p <.001). Females foraged (F:23.7%,M:20.6%) and rested (F:46.7%,M:42.7%) more than males, while males spent more time in social behavior (M:18.9%,F:12.8%) and movement (M:1.2%,F:.79%) (Santorelli et al. 2006). During feeding, females exhibit social dominance, although clear male submissive signaling is frequently not apparent (Patel 2003b). During the resting bouts, there is regular social interaction such as grooming and playing between preferred partners. Play bouts on the ground have been observed for over 30 minutes (Patel, pers. comm.). As in other rainforest sifakas, rates of aggression are very low, with affiliative behaviors between females being far less common (not “female-bonded”) than those between males and between the sexes (Patel 2003b).

Although there has never been a true study of the diet of the silky sifaka, it is clear that silky sifakas are folivorous seed predators, like other rainforest sifakas. A preliminary study during a fraction of the non-fruiting season found that over 75% of food intake consisted of mature or young leaves, while fruit and seeds make up around 15% of the diet, flowers 7% and the remainder bark and soil that are consumed very occasionally (Kelly and Mayor 2002).

The dispersal pattern has not yet been established, although a single young adult male disappeared in 2002 just prior to the mating season after an intense fight with another male just prior to the mating season. Before disappearing, he had become spatially peripheral from the rest of group for several weeks which is consistent with male emigration. Instead, this male may have been killed and eaten by the fossa. As is true of other rainforest sifakas, fossa are the only documented predator of the silky sifaka other than human beings (Patel 2005). No aerial predation attempts by raptors have ever been observed, although silky sifakas sometimes stare skyward and emit “aerial disturbance” roars in the presence of the Madagascar Buzzard (Patel et al. 2003a). Interestingly, the diet of the Madagascar Buzzard has been well studied and does not include Propithecus (Berkelman 1994). Silky sifakas, like verraux’s sifaka, lack highly specialized alarm vocalizations against terrestrial predation (Patel et al 2003a, Fichtel and Kappeler 2002). However, the “Zzuss” general disturbance vocalization does communicate the identity and sex of the caller (Patel et al. 2005b, Patel et al. 2006).

Actual mating occurs over just a few days or less each year during the mating season of November, December, and January with infants being born in June or July. Infants initially grasp the fur on their mother’s belly and later (after around four weeks) transfer to ride on her back. Until the approach of maturity, offspring sleep with their mothers all the time. As is typical of Propithecus, all group members interact affiliatively with infants. Grooming is the most frequent alloparental behavior followed by playing, carrying, and nursing respectively. Remarkably, mothers have even been seen nursing their own and other offspring simultaneously (Patel et al. 2003b).

In addition to at least 7 distinct adult vocalizations (Patel et al. 2005a), silky sifakas communicate extensively through their highly developed sense of smell. Females scentmark tree trunks with their ano-genital region in a rhythmic vertical motion, while males scentmark with their chest (sternal-gular marking), their ano-genital region, and both types combined in sequence. Like Milne-Edwards’ Sifakas, male silky sifakas scentmark at higher rates than females throughout the year but at highest rates during the mating season. Female scentmarks are responded to by other group members far sooner and more often than male scentmarks. Males also engage in far more over-marking than females, in which a scentmark is placed directly on top of a previous recently deposited scentmark of another group member. Silky sifaka scentmarks are generally deposited within the core area of the home-range as opposed to on the boundaries of the territory (Patel 2006). Totem-tree scent-marking has been documented in the silky sifaka in which scent-marks are preferentially deposited on particular trees predominantly by adult males within the core area of the home-range. In large part, totem-tree scentmarks are due to male over-marking and male counter-marking the scent-marks of females and other males (Ritchie and Patel 2006).

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