Propithecus verreauxi
Verreaux's sifaka

Verreaux's sifakas are found in the western and southwestern regions of Madagascar. (Nowak, 1999; Walker, 1968)

Verreaux's sifakas are primarily arboreal and are found in deciduous and evergreen forests. However, they are widespread and can also be found in wet and dry habitats throughout southwest Madagascar. (Dewar and Richard, 2007; Wade, 1996; Walker, 1968)

Verreaux's sifakas have distinct coloration with white fur and a hint of yellow contrasting their hairless, black face. Their hands and feet are also black. They have a long tail that ranges from 43 to 56 cm in length, roughly the same length as their body (45 to 55 cm). Verreaux's sifakas are not sexually dimorphic, as both males and females weigh between 3 and 7 kg. (Nowak, 1999)

Verreaux's sifakas form social hierarchies, which are subject to change during the mating season as females only breed with dominant males. Subordinate males challenge dominant males, often resulting in intense competition and fighting. (Lewis, 2005; Nowak, 1999)

Verreaux's sifakas scent mark as a form of communication. Females scent mark to get the attention of males. Subordinate males scent mark to get the attention of females, and dominant males scent-mark to claim territory. Scent-marking often results in conflict among males. (Lewis, 2005; Nowak, 1999)

Verreaux's sifakas breed from late January through March. Following implantation, gestation lasts 130 to 141 days. Typically, mothers give birth to only one offspring per year, which occurs between June and September. Average birth weight is 40 g. Mothers carry young close to their abdomen and chest for the first 2 to 3 months of the offspring's life. At about 3 months old, young move to their mothers back until they reach 5 to 6 months of age and are weaned at about six months. Young sifakas reach adult size at 21 months and are sexually mature by two and a half years old. (Nowak, 1999)

Verreaux's sifakas live in social groups and young are cared for by adults. A mother's position in the social hierarchy affects the social status of her young and parental care continues until young reach full size at about 21 months. Females stay with the group, while males either stay with the group or leave to form their own. Mothers carry newborn sifakas near their chest and abdomen for the first 2 to 3 months after birth and then on her back until offspring reach about 6 months of age. (Nowak, 1999)

Little is known about the lifespan of Verreaux's sifakas in the wild, as the residents of Madagascar rarely come into contact with them. Studies have found that they have a surprisingly low parasitic load, which may result in increased lifespan relative to other closely related primates. The average lifespan of captive Verreaux's sifakas is 18 years with a recorded maximum of 23.5 years. (Muehlenbein, et al., 2003; Nowak, 1999)

Verreaux's sifakas are social primates that live in hierarchical groups of 2 to 13 individuals. Groups consist of 5 to 7 adult females, 2 to 3 adult males, and a few young. Male group members consist of a single, dark-chested male (stain-chested males) that mates with group females, and 1 or 2 subordinate males (clean-chested males) with monochromatically colored chests. Within-group violence is rare during the non-breeding season. However, non-physical confrontations may occur between groups defending their respective territories via scent marking, jumping toward the opposing group, barking, clucking, and growling. Scent marking is also used to claim food, territory, and mates, and to communicate one's presence. Scent markings can be made by urine or from a scent gland located in the throat of stain-chested males. Females and subordinate males scent mark territorial boundaries, while stain-chested males may randomly scent mark throughout the entire territory. In general, females scent mark less than males and males often mark over female markings. (Dunham, 2008; Erkert and Kappeler, 2004; Fichtel and Kappeler, 2002; Lewis, 2005; Lewis, 2006; Nowak, 1999; Walker, 1968; Wunderlich and Schaum, 2007; Young, et al., 1990)

Verreaux's sifakas exhibit female dominance, as do all lemurs and lemur relatives on Madagascar. While a single evolutionary cause of female dominance in Malagasy primates has yet to be fully supported, one hypothesis suggests sexual monomorphism as a potential cause. The hypothesis proposes that, because males and females are of similar size, males have no immediate dominance over females. As a result, female dominance is thought to be linked to their reproductive abilities, which play an important role in group structure and longevity. (Dunham, 2008; Erkert and Kappeler, 2004; Fichtel and Kappeler, 2002; Lewis, 2005; Lewis, 2006; Nowak, 1999; Walker, 1968; Wunderlich and Schaum, 2007; Young, et al., 1990)

Verreaux's sifakas are diurnal and typically active during morning and late afternoon, during which time they feed while sunning on tree branches that are about 13 m from the ground. Generally, they sleep in the forest canopy from dusk until dawn. (Dunham, 2008; Erkert and Kappeler, 2004; Fichtel and Kappeler, 2002; Lewis, 2005; Lewis, 2006; Nowak, 1999; Walker, 1968; Wunderlich and Schaum, 2007; Young, et al., 1990)

Verreaux's sifakas are often described as a vertical clingers and leapers (VCL). Using their hind legs, they can leap up to 10 m from one tree limb to the next. Unlike many other primates, they also makes use of a highly specialized form of bipedal movement while on the ground. This unique form of saltatorial movement is made possible by their strong, lengthy hind limbs. Two different speeds of bipedal locomotion are used, a slower walking gait and a more rapid pace that contains a brief aerial phase. During saltatorial movements, they use their arms to increase balance by throwing them above their head in rhythm with leaping movements. Finally, Verreaux's sifakas rarely use their hands during feeding. Instead, a swooping motion with the entire body is made, as food directly enters the mouth. (Dunham, 2008; Erkert and Kappeler, 2004; Fichtel and Kappeler, 2002; Lewis, 2005; Lewis, 2006; Nowak, 1999; Walker, 1968; Wunderlich and Schaum, 2007; Young, et al., 1990)

Verreaux's sifakas have home ranges of 2.2 to 2.6 ha. Groups move as a single unit, leaving no individuals behind. Daily travel distances vary in relation to season. Movements average about 1,100 m/day during the rainy season and 750 m/day during the dry season. Population densities in south and southwestern Madagascar range from 50 to 500 individuals per km^2. (Nowak, 1999)

Verreaux's sifakas communicate over long distances via clear, deep barks. Barks sound similar to the word “sifaka” and are produced only when intruders are nearby. Barks are generally made by the group leader, and if group cohesion is ever threatened by an outsider, growling or barking is produced to ward off intruders. (Nowak, 1999; Palagi, et al., 2008; Trillmich, et al., 2004; Young, et al., 1990)

Scent marking is an additional form of communication used by Verreaux's sifakas. It serves multiple purposes including marking territory, making one's presence known (specifically females in estrus), claiming food or territory, attracting mates, and may be used during non-physical competition. Scent marking is a versatile and important way of communicating in Verreaux's sifakas. (Nowak, 1999; Palagi, et al., 2008; Trillmich, et al., 2004; Young, et al., 1990)

Verreaux's sifakas are herbivorous and feed primarily on leaves, bark, and flowers. When abundant, fruit may also be incorporated into their diet. Nutrition levels directly coincide with season and rainfall amounts, with food of higher nutritional value being most abundant during the wet season. (Nowak, 1999; Walker, 1968)

Verreaux's sifakas commonly use alarm calls to warn group members of the presence of a predator. Different alarm calls are given for aerial (harrier hawk, Polyboroides radiatus) and terrestrial predators, which includes fossas (Cyptoprocta ferox) and stray dogs (Canis lupus familaris). Alarm calls are performed by males and females of all ranks in the social hierarchy and are thought to be most effective in group settings. As group size increases the number of individuals able to spot potential predators increases. As a result, group cohesion is an important aspect of deterring predators. It is also thought that large groups are able to intimidate potential predators more easily than small groups. (Fichtel and Kappeler, 2002; Trillmich, et al., 2004)

Verreaux’s sifakas are an important prey item for fossas (Cyptoprocta ferox), stray dogs (Canis lupus familaris), and harrier hawks (Polyboroides radiatus). Also, they are strict herbivores and considered to be important seed dispersers. (Fichtel and Kappeler, 2002; Muehlenbein, et al., 2003; Nowak, 1999; Trillmich, et al., 2004)

Verreaux’s sifakas are the most extensively studied of the Malagasy prosimians and have been the subject of a wide range of research topics. These topics include, but are not limited to bipedalism in mammals, the evolution of social hierarchies, the causes and consequences of female dominance in mammals, the evolution and ecological consequences of male dimorphism, the causes and consequences of decreased parasitic loads, and the evolution of characteristics that are necessary for living in the variable environments of Madagascar. Verreaux's sifakas are also an important component of the unique Madagascar ecosystem, which attracts tourists from around the globe. (Fichtel and Kappeler, 2002; Lewis and Kappeler, 2005; Nowak, 1999; Trillmich, et al., 2004; Wunderlich and Schaum, 2007; Young, et al., 1990)

There are no known adverse effects of Verreaux's sifakas on humans.

Verreaux's sifakas are rapidly losing their natural habitat. Due to slash-and-burn agriculture, the deciduous forests of Madagascar are severely threatened. Additionally, Malagasy forests have been subjected to commercial logging, overgrazing by livestock, and charcoal manufacturing. Fortunately, captive breeding has been successful in Verreaux's sifakas, which, according to the IUCN Red List, are considered "vulnerable". (Loudon, et al., 2006; Nowak, 1999)