Propithecus edwardsi

Geographic Range

Propithecus edwardsi is found only on the island of Madagascar which lies off the southwest coast of Africa. They are only found in a small area of southeastern Madagascar from the Mangoro and Onvine rivers in the north to the Rienana River in the south, within the Andringitra National Park. Formerly they probably occurred as far south as the Manampatrana River. A clinal gradient seems to be expressed between Propithecus edwardsi and Propithecus diadema due to a change in environments. They are both found in the same area but P. diadema is found on more inland mountain ranges.

• Biogeographic Regions
• ethiopian ethiopian
  • native native

• Other Geographic Terms
• island endemic island endemic

Habitat

Milne-Edward's sifakas live on the eastern coast of Madagascar in the coastal mountain range in primary and secondary forest habitats from 600 to 1600 m elevatiion. Forested habitats in these mountains have been reduced by human exploitation, although areas are now protected in refuges.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• rainforest rainforest
• mountains mountains

Physical Description

Milne-Edward's sifakas are black or chocolate brown sifakas with white patches on the hind legs and back. These white patches are not always present and sometimes are replaced by silver-tipped hairs. They have a short, naked black face with forward facing eyes for increased depth perception. The ears are also naked but generally covered by the fur on the head. Males have a dark black or brown gular gland. Their eyes are orange-red. Head and body length is from 42 to 52 cm, tail length is from 41 to 48 cm, and weight is from 5 to 6.5 kg.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Milne-Edward's sifakas are generally not monogamous for life. Family groups normally have one adult pair which reproduces. The rest of the family group is usually the offspring of this pair. During the mating season, towards the end of May, males sometimes move through groups, which helps to maintain diversity in the gene pool. Milne-Edward's sifakas currently tend to live in somewhat larger groups because of the restriction of their home ranges due to habiat loss. Males use their gular glands to stimulate estrus in females. They mark trees and branches and even mark the fur on the head and back of the members of the opposite sex. Males follow females smelling their genitalia to determine mating readiness.

• Mating System
• monogamous monogamous

Milne-Edward's sifakas reproduce slowly. Females reproduce every other year, with birth in June and July. Family groups tend to have one pair of breeding adults, the rest of the group are their offspring from past seasons. Groups typically only grow by one or two new members every breeding season.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

Milne-Edward's sifaka young are carried on their mother's stomach until they are ready to latch onto their backs at about 3 to 4 weeks old. Once an infant sifaka starts to try climbing and leaping on its own, it is not unusual to see them fall. Sifakas learn by watching adults. When a mother sifaka sees that her young as fallen, she goes to take care of it. Females are usually in charge of taking care of the infants. However, it is not uncommon to see male sifakas providing food to females to give to their young and sometimes the young of others.

• Parental Investment
• precocial precocial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • male
    • female
  • protecting
    • female
• post-independence association with parents
• extended period of juvenile learning

Lifespan/Longevity

Milne-Edward's sifakas can live a long time and reproduce slowly. Almost half of all young Milne-Edward's sifakas do not survive beyond 1 year because of predation and stress associated with habitat loss. Some mortalities of young are the result of infanticide by males from outside of family groups.

Behavior

Milne-Edward's sifakas are found in small family groups of 3 to 9 individuals. They use vertical clinging and leaping to move through their complex, forested habitats. Their excellent depth perception is used to carefully pick their landing spot. They use their powerful hind legs to launch themselves from a tree, then swing their body around in mid-leap to land hind legs first on the target tree. They do not move around on ground well because they have short legs and longer arms. Their feet are semi-digitigrade and they have an opposable hallux for clinging to branches. While foraging they move more slowly on thinner branches. They use larger trees and branches for travelling. They have a tooth comb formed by their bottom incisors that is used for personal and social grooming. Play behaviors seem to occur more during the wet season and grooming occurs during periods of rest. Occasionally members of the family group greet each other with a brief nose-touch.

• Key Behaviors
• arboreal arboreal
• scansorial
• saltatorial saltatorial
• diurnal diurnal
• motile motile
• sedentary sedentary
• social social

Home Range

Groups of Milne-Edward's sifakas typically range over 100 to 250 hectares. Population densities are estimated at about 8 individuals per square kilometer.

Communication and Perception

Milne-Edward's sifakas use different sounds to communicate. “Moos” are used to inform others of group’s location. Warning calls include a sudden “zusss” sound to warn of enemies on the ground and barking, which warns of aerial threats. When they are lost, individuals whistle to let their group know where to find them. Allogroooming is a form of tactile communication and it is likely that other forms of touch and body language are used among individuals. Scent marking by males is a form of sexual communication.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• scent marks scent marks

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Milne-Edward's sifakas are mainly frugivores, but they also eat leaves, seeds, and flowers. They eat a wide variety of plants on a daily basis and throughout the year, with their diet varying with seasonal availability of foods.

• Primary Diet
• herbivore herbivore
  • frugivore frugivore

• Plant Foods
• leaves
• wood, bark, or stems
• seeds, grains, and nuts
• fruit
• flowers

Predation

Milne-Edward's sifakas are preyed on by fossas ( Cryptoprocta ferox ). In order to avoid these predators they use their jumping speed which surpasses the speed of a fossa in the trees. Young may also be preyed on by large raptors, although this has not been documented.

Ecosystem Roles

Milne-Edward's sifakas eat fruit which helps to disperse the seeds of the trees they forage in. They also help to create awareness of endangered endemic species and generate support for forest conservation in Madagascar.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Milne-Edward's sifakas are sometimes hunted for food, but hunting is restricted due to difficulty acquiring guns. They also create a need for selective logging so that the remaining forest has the characteristics necessary to support populations of Milne-Edward's sifakas. They are an important and charismatic member of native Malagasy forests.

• Positive Impacts
• food food
• ecotourism ecotourism
• research and education

Economic Importance for Humans: Negative

Milne-Edward's sifakas have no recorded negative impacts on humans.

Conservation Status

Milne-Edward's sifakas are endangered primarily because of habitat loss. Over the past thirty years the total wild population has decreased by more than 50%. It is predicted that the population will experience another 50% decrease over the next three years. Loss of habitat is due to logging, gold mining, and illegal rum production. Other human impacts include hunting, mostly in the northern part of their habitat. Hunting and deforestation are considered the most serious threats to Propithecus edwardsi populations. In an effort to help conserve the species there are a few national parks set aside in their range. There are reports of them living in some forests outside of these parks. There are no known captive populations.

Additional Links

Encyclopedia of Life

Contributors

Lorraine Negron (author), University of Michigan-Ann Arbor, Robin Weber (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor, Tanya Dewey (editor), Animal Diversity Web.

References

Gould, L., M. Sauther. 2006. Lemurs: Ecology and Adaptations . New York: Springer.

Konstant, W., F. Hawkins, E. Louis, O. Langrand, J. Ratsimbazafy, R. Rasoloarison, J. Ganzhorn, S. Rajaobelina, I. Tattersall, D. Meyers. 2006. Lemurs of Madagascar . Colombia: Conservational International.

Tattersall, I., R. Sussman. 1975. Lemur Biology . New York and London: Plenum Press.

Tattersall, I. 1982. The Primates of Madagascar . New York: Columbia University Press.

jrank.org, 2009. "Sifakas, Avahis, and Indris: Indriidae" (On-line). Animal Life Encyclopedia. Accessed July 27, 2009 at http://animals.jrank.org/pages/2952/Avahis-Sifakas-Indris-Indriidae.html .

2008. "IUCN Redlist" (On-line). Accessed April 08, 2009 at http://www.iucnredlist.org/details/18359 .