As a result of the long period of bio-geographical separation, the Mentawai islands have evolved an unusually high degree of biological richness and species endemism. Of the 34 mammal species for example, at least 17 are endemic (WWF 1982; Whitten et al. 2000; Roos et al. 2003), more than on the entire main island of Sumatra. More than twelve bird taxa are also known to be unique to these islands, whilst the number of endemic animal species on lower taxonomic levels can currently only be estimated. As a result of this exceptional level of endemism, the Mentawai archipelago is often referred to as the “Galapagos of the east”.

Of the endemic mammals, undoubtedly the most striking are the primates. According to current classification, these include 2 macaque species, 2 langur species and Kloss´gibbon. Four of these are found on Siberut and all are threatened as a result of habitat loss (IUCN status ranges from vulnerable to critically endangered). The Pig-tailed langur, Simias concolor, is currently listed as one of the worlds 25 most endangered primates.

(c) Steven D. Nash, 2006 (Mentawai primates)

© Stephen D. Nash/IUCN SSC Primate Specialist Group

The survival of these primates as well as that of many of the other animal and plant species on Siberut, depends on immediate conservation action and the protection of Siberut´s wildlife has been ranked as a priority, even within the “Sundaland Hotspot of Biodiversity” (Conservation International, 2002).

The Siberut Conservation Project is currently the only international organisation jointly involved in scientific studies and applied conservation in this region.

(c) Erb, 2005 (Simias concolor)
(c) Tess, 2005 (Presbytis potenziani)

The pig-tailed langur (Simias concolor) is the only representative of its genus and belongs to the 25 most endangered Primates worldwide.

(c) Richter, 2008 (Macaca siberu 1)

The other Colobine monkey, the Mentawai langur (Presbytis potenziani) is considered by some to be the only old world monkey with a monogamous mating system. Both Langur species live sympatrically throughout the remaining forests of Mentawai.

As discovered recently by SCP scientists, the Mentawai islands are home to two distinct species of macaques. Macaca pagensis, living on the three southern islands and Macaca siberu (depicted here), livinge exclusively on the island of Siberut. SCP has initiated the first comparative studies on these primates, yet poorly known to science.

(c) Hilgartner, 2007 (Hylobates klossii)
(c) Hilgartner, 2007 (Mentawai Civet)

The Kloss gibbon (Hylobates klossii) is characterized by its monochromatic black fur and its remarkably beautiful songs. In contrast to other gibbons males and females do not duet but sing at different times of the day. When neighbouring groups simultaneously call, their songs resound throughout the forest and can be heard from a great distance.

The Mentawai civet Paradoxurus hermaphroditus lignicolor represents another relatively large mammal species endemic to the Mentawai islands.

(c) Riedelbauch, 2006 (Otus mentawi)
(c) Abegg, 2005 (Draco volans)

The Mentawai scops owl (Otus mentawi) is one of the 12 bird species known to be unique to the archipelago.

(c) Hilgartner, 2007 (Tree Snake)

The so called “flying dragon” (Draco volans) is an arboreal lizard (Agamidae), able to glide from tree to tree on winglike skinlaps.


This tree snake is neither aggressive nor venomous as proofed by an accidental bite during a short handling of this individual at SCP-field station.

(c) Hilgartner, 2007 (Pitviper)
(c) Hilgartner, 2007 (Frog - Rana)

Also not aggressive but quite venomous is this pitviper (Trimeresurus spec.), at times seen next to brooks, motionless waiting for prey.

(c) Hilgartner, 2007 (Mantis)

Frogs of the genera Limnonectes, Rana (depicted here) and Polypedates as well as toads of genus Ansonia belong to the more frequently encountered amphibians in North Siberut.

(c) Ziegler, 2006 (Hunting spider)

A representative of the genus Mantis, found in a fig tree at about 30 meter above the ground.

(c) Ziegler, 2006 (Atlas Moth)

A hunting spider on the wall of one of the SCP -fieldstation buildings is guarding a silk egg sac to protect its offspring.

Named after a Titan of Greek mythology the Atlas moth (Attacus atlas) is one of the worlds largest representatives of the order Lepidoptera, with a wing surface area of more than 400cm2. The individual shown here was attracted by the lights of the SCP-field station.

→ Top of the page

© Siberut Conservation Programme 2009-2013 I Site Map I Contact us I Privacy Policy

  Last Update: 18.12.2013