This is “William”  one of a pair of North Borneo Gibbons Hylobates funereus that “own” the gibbon territory next to the Belalong Canopy Walkway in the Ulu Temburong National Park in Brunei.  In his right hand William is holding a piece of ripe Ficus punctata fruit  collected from a nearby fruiting liana.

GIBBON FAMILY TERRITORIES IN BORNEO:    Researchers believe that the Ulu Temburong forests host the most dense population of gibbons in  the whole of Borneo.

Location Territy Ha Families/km2 Habitat
Gng Palung 28 3 Lowland dipterocarp
Sabangau 47 2 Peat-swamp
Tg Puting 48 2 Peat-swamp
Kutai 36 3 Lowland dipterocarp
Kayan Mentarang 42 2 Hill forest
Temburong  Bukit Tudal (1) 31 3 Hill forest
Temburong Belalong (2) 19 5 Lowland dipterocarp
Average 36 2  
  • (1) Bennett et al (1987) A Wildlife Survey of Ulu Temburong
  • (2) Cranbook & Edwards (1994) A Tropical Rainforest

Gibbon familes average 3.5 to 4  individuals and strongly defend their territories with loud early morning calls. The high density  and small family territories of gibbons at both sites in Ulu Temburong (Brunei) may be due to the absence of orangutans in Brunei. Orangutans are known to eat unripe F. punctata figs. Gibbons only eat the ripe figs and therefore cannot compete with orangutans if they are present.

This is  “Kate”, Williams partner  hanging from one arm next to a Ficus punctata  liana covered in ripening figs at the Belalong Canopy Walkway in Brunei.  Kate is larger and much bolder than  “William”.   At the time these photos were taken, William and Kate were childless. Their first baby  Wak-Wak was born in the middle of 2017.  All photos by Quentin Phillipps, taken in December 2016.
Kate Gibbon  with fig 3P7A4480.JPG
Note that Kate is holding a large, dark purple, ripe Ficus punctata fig fruit  in her left hand. This one Ficus punctata liana fruits prolifically approximately 4 times a year.  The figs do not ripen in one big bang but individually over a period of 2 months  before starting another crop around 2 months later. Thus this one prolific Ficus punctata liana provides  food intermittently  for this one gibbon family for about half the year. Other animals  that fed on the figs include binturongs, striped palm civets, long tailed macaques and Prevost’s Squirrel.
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View from the far tower of the the Belalong Canopy Walkway  at Temburong, Brunei. The  surrounding forests host  both the greatest variety and density of figs  known in Borneo.  This photo alone includes 5  different fig species !   Maybe this is the reason that the Temburong gibbons are able to survive in relatively small territories.


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Illustration  by Karen Phillips from page 185,  of the Phillipps’ Field Guide to the Mammals of Borneo by Quentin and Karen Phillipps. (2016)
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View from the Belalong Canopy Walkway looking north west towards  Brunei Bay. The long ridge in the far distance defines the border between Temburong, Brunei and Limbang, Sarawak.

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