Decken’s sifaka (Propithecus deckenii)

A little-known species of sifaka, Decken’s sifaka was formerly considered a subspecies of Verreaux's sifaka (Propithecus verreauxi) ⁽¹⁾. Its fur is typically creamy white, which forms a stark contrast against the black, hairless face. The neck, shoulders, back and limbs are occasionally tinged with yellow, silvery-grey or pale brown ⁽²⁾. In some areas, melanistic individuals have been observed; these sifakas have a dark brown to black head, and light brown to silvery-grey areas on the upper arms, shoulders and upper back, and the chest and under surface of the arms are dark brown ⁽²⁾.

Synonyms

Propithecus verreauxi deckenii.

Size

Total length: 92.5 – 107.5 cm ⁽²⁾

Head-body length: 42.5 – 47.5 cm ⁽²⁾

Tail length: 50 – 60 cm ⁽²⁾

Weight : 3.5 – 4.5 kg ⁽²⁾

As Decken’s sifaka is yet to be the subject of a comprehensive study in the wild ⁽¹⁾, information on its biology is lacking. A diurnal primate, it is known to live in groups of two to ten individuals, and whilst the composition of the groups is not clear, groups with two adult females, both with young, have been observed ⁽²⁾.

Like all sifakas, this species has long, powerful legs used to propel itself between trees whilst keeping its body upright; this highly specialised method of locomotion is known as vertical clinging and leaping ⁽⁴⁾.

Found only in western Madagascar, Decken’s sifaka occurs in suitable patches of forest between Manambolo River in the south and Mahavavy River in the north ^{(1) (2)}. The precise range of this species is hard to determine, largely due to the occurrence of the closely-related crowned sifaka (Propithecus coronatus) in the same region. In some areas, hybridisation may even take place between these two species ^{(1) (2)}.

Decken’s sifaka typically inhabits dry, deciduous forest ⁽²⁾, although it is apparently able to survive in rather degraded habitat and has even been found in Eucalyptus trees in the middle of the town of Soalala ⁽¹⁾.

Decken’s sifaka is classified as Vulnerable (VU) on the IUCN Red List ⁽¹⁾, and listed on Appendix I of CITES ⁽³⁾.

The loss of its forest habitat poses the greatest threat to Decken’s sifaka. Already fragmented forests in western Madagascar are being reduced further to produce charcoal and to create pasture for livestock ⁽¹⁾. Unlike many other sifakas, Decken’s sifaka is fortunately not currently threatened by hunting, due to a strong taboo among local people in much of its range. However, the situation should be carefully monitored, as a breakdown of hunting taboos would likely lead to Decken’s sifaka becoming more threatened ⁽¹⁾. 

Decken’s sifaka occurs in a number of protected areas, including Tsingy de Bemaraha National Park, Baie de Baly National Park, Tsingy de Bemaraha Strict Nature Reserve and Ambohijanahary Special Reserve ⁽¹⁾. This, alongside its listing on Appendix I of the Convention on International Trade in Endangered Species (CITES) which prohibits international trade in this species ⁽³⁾, should hopefully go some way in preventing further declines of this striking primate.

To find out more about the conservation of Madagascar’s primates see:

• Duke Lemur Centre:
  http://www.lemur.duke.edu
• Wildlife Conservation Society:
  http://www.wcs.org/where-we-work/africa/madagascar.aspx

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

Diurnal

Active during the day.

Hybridisation

Cross-breeding between two different species or subspecies.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

1. IUCN Red List (March, 2010)
   http://www.iucnredlist.org/
2. Garbutt, N. (2007) Mammals of Madagascar: A Complete Guide. A&C Black Publishers Ltd.
3. CITES (March, 2010)
   http://www.cites.org
4. Macdonald, D.W. (2001) The New Encyclopedia of Mammals. Oxford University Press, Oxford.