Tawau: a key mammal-watching destination in Borneo.
Authors: Shavez Cheema and Martin Parry of 1StopBorneoWildlife
During the 21st century, until 2020, mammal watching in Borneo had shown a steady rise in popularity although the populations of the mammals themselves have often been declining. Organised groups of watchers usually come to observe our wild cats, flying squirrels, primates, civets and more; and when they arrive, they normally head for Sabah. Improving transport and logistics has meant that well Sabah’s Parks and other well known ‘mammal spotting’ areas are more accessible than before; lowland and montane forests, rivers and coastlines can often be explored on organised tours. Kinabalu National Park, Kinabatangan River and Danum Valley Conservation Area, are examples of well-established destinations for wildlife tourism despite being surrounded by extensive cultivation, especially palm oil plantation. Others, such as Deramakot Forest Management Unit, have been developed to combine sustainable conservation with agricultural business, in this case selective logging for timber.
However, if there is one destination on Borneo to be handpicked for mammal watchers, it should be the district of Tawau in the South East of Sabah; it can boast an amazing diversity of habitats and mammals. There are drives and walks to spot wild cats, boat trips for mangrove and marine mammals, and trekking for lowland and montane forest species. The district also benefits from containing Tawau Hills Park, a protected area of primary rainforest amidst a sea of oil palm. Below is a brief description of 15 species that make Tawau perhaps the best destination for mammal watching on Borneo.
To watch them is a beginning, but we hope that the species themselves will inspire you to want to learn more about them and their ecology and so become involved in their conservation. All 15 photographs in this series have been taken in the Tawau district since 2020.
G: with a professional guide, there is a good chance to see in Tawau.
T: possible to see in Tawau but quite tough, as it also is elsewhere Borneo.
Should you wish to become involved in mammal conservation in Borneo, here is a list of organisations to contact:
Borneo Nature Foundation at: https://www.borneonaturefoundation.org/ s.cheyne@borneonature.org
1StopBorneo Wildlife at: www.1stopborneo.org1stopborneo@gmail.com
Project Borneo at: https://www.projectborneo.org/ info@projectborneo.org
Planet Indonesia at: https://www.planetindonesia.org/ admin@planetindonesia.org
Bringing back our rare animals at: https://www.bringingbackourrareanimals.org/
1.) North Borneo Gibbon (Hylobates funereus) G
The North Borneo Gibbon is one of four gibbon species endemic to Borneo that differ mainly in coat colour. The picture shows it lacks a tail but possesses long, powerful forearms that allow gibbons to swing from tree to tree using the arms alternatively, a behaviour known as brachiating; this enables rapid progress in dense vegetation so that an inexperienced observer may struggle to keep up with their progress, instead seeing branches still moving after they have passed through. They are also able to walk upright along branches. A small family group comprises parents and children; the male and female duet, producing a ‘wa-wa-wa...’ call, a defining sound of the Borneo rainforest. The male begins at about 0415h, just before dawn, and then the female joins him in a ‘dawn duet’ that seems to energise the awakening forest. They forage over large territories fruit and leaves over a wide area, swiftly moving through it in a regular circuit. Habitat destruction threatens these territories and it is only in areas where mature rainforests are undisturbed, such as in Tawau and other parts of E. Sabah, that gibbon populations are stable.
2.) Proboscis Monkey (Nasalis larvatus) G
Many descriptions of the proboscis monkey begin with: ‘this strange’ or ‘this bizarre-looking’ monkey and certainly it is quite different from all other primates of Borneo. A large, adult male displays an elongated nose that is thought to amplify his dominant calls, for example when defending his harem against rivals; in fact; these monkeys are quite noisy, with a wide range of noises ranging from honking to squealing. Females, such as the one in the image here, have a much smaller nose; the long tail of both sexes often hangs down vertically when sitting in a tree and the picture shows that it is also very obvious when an individual is on the ground. This monkey is endemic to Borneo and largely found along banks of forest rivers, coastal areas and in mangrove swamps. They are usually arboreal, living in troops of up to 30 that roost in trees overhanging water; young males join smaller ‘same-sex’ troops until they are mature enough to challenge to take over a harem; this may take up to 10 years since an alpha male is over 20kg in weight and a powerful animal.
3.) Bornean Clouded Leopard (Neofelis diardi borneensis) T
The most likely places in Borneo to see its biggest cat are all in East Sabah, where increasingly sightings are in logged forests, probably because they support greater numbers of prey species such as deer and bearded pig. It is the apex predator of many habitats, often hunting in the canopy and so prey may be varied, including proboscis monkeys, langurs and young orang utans.
The individual here, a female, displays the characteristic ‘dark cloud’ pattern along the flank. Full-grown males are heavier, reaching over 20kg, approaching twice the weight of the smaller females. It is normally nocturnal, resting up in the canopy during the day. The adaptation to hunting in logged forest means that the loss of rainforest habitat may not threaten clouded leopard numbers although increased risk of contact with humans may make them more susceptible to poaching.
4.) Marbled Cat (Pardofelis marmorata) T
Like the larger clouded leopard, the marbled cat is a scarce forest-dweller; it is considerably smaller, weighing up to 5kg for a large adult. The image below shows that the two cats share similar patterns of ‘black blotches on brown fur along its flanks, although it is less distinct in the marbled cat. The tail is longer than the body, adapting it for tree climbing, when it can flatten against a trunk (see picture) and even descend head first (as can the clouded leopard). It is a nocturnal hunter with rats taken on the ground as well as other mammals such as flying squirrels in the canopy, where the large tail enables great agility.
This shy, attractive cat is a rare inhabitant of lowland forests and its population remains threatened by deforestation; it has been observed hunting in logged forests but not to the extent of the clouded leopard.
5.) Irrawaddy Dolphin (Orcacella brevirostris) G
This picture taken close to Tawau’s coast shows the characteristic appearance of the Irrawaddy dolphin: a high, rounded forehead without an obvious ‘beak’, quite different from the streamlined head of most other dolphins.
Also shown is the blue-grey colour of the upper body and the short dorsal fin located two thirds of the way down its back. This is a dolphin adapted for inshore waters and estuaries rather than streamlined for ocean swimming. They are small dolphins (up to 2.5m in length); sometimes, as shown here, they may ‘breach’ but often they are inconspicuous, hunting fish in murky water by using sonar. In Tawau, they have been spotted following local fishing boats for discarded fish; it has been suggested that they may be ‘fishing cooperatively’ by driving fish towards fishermen’s nets in return for a reward from the catch.
6.) Indo-Pacific Hump-Backed Dolphin (Sousa chinensis) G
This is a larger and more ‘camera-friendly dolphin, measured at over 2.8m, and, although scarce in all locations, it is widely distributed in coastal waters along the eastern Indian and western Pacific Oceans. In Borneo, it is most likely to be spotted in river estuaries and the ones pictured were seen in the same location as a pod of Irrawaddy dolphins from which is readily distinguished by an obvious ‘beak’, lighter upper body and humped back with larger dorsal fin.
These dolphins can show colour variation, perhaps age related, from grey to white, even pink, with some showing intermediate speckling as shown here; in waters around Hong Kong, for example, where sightings have increased due probably to reduced high speed ferry traffic during the COVID19 pandemic, it is known as the Chinese White Dolphin.
7.) Bornean Pigmy Elephant (Elephas maximus borneensis) G
A pigmy only by elephant standards, this is Borneo’s largest land animal with mature males reaching an imposing 2,500kg and 2.5m in height.
Habitat loss and conflict with humans means that elephants are critically endangered in Borneo; they require large areas to find their preferred food that includes wild fruits, grasses and bamboo; an estimated 1,500 remain, with almost all of these in Sabah, where they typically form small family groups in flat, forested areas with access to water. Reports of elephants being killed during encroachment into oil palm plantations and other cultivated land are not unusual. Some groups are almost permanent residents in plantations and, in a few, innovative approaches have been developed to manage human/elephant interactions so as to limit commercial damage and promote ‘elephant tourism’.
8.) Red Leaf Monkey (Presbytis rubicunda) G
This charming red langur is the commonest of 6 species of langurs (leaf-eating monkeys) occurring in Borneo. It is found in the lowland forests of Tawau but also elsewhere in Sabah, in the cooler, mountain forests of Kinabalu Park and the Crocker Range, where they have thicker coats. They have a similar colour to the much larger orang utan from which they can also be distinguished by possession of a long tail and quicker, more agile movement in trees.
They are also most likely to be seen in groups of 8 or below, whereas the orang utan is a solitary primate. In Tawau Hills, ‘white morphs’ are seen: adults that retain the juvenile white coat throughout their lives. Observing a group of red langurs is likely to be a highlight of any forest walk and sometimes they may come to meet you (see picture)!
9.) Small-Clawed Otter (Aonyx cinerea) G
This is the smallest of the four species of otter found in Borneo; unfortunately hidden by estuarine mud in this picture, the fore paws are ‘hand like’, with only rudimentary claws, since they feed by hunting shrimps, crabs and molluscs. The traditional hatred of otters by fisherman ’because they eat our fish’ shouldn’t apply to this species.
This and the larger Smooth Otter are social species, living and hunting in their family groups, in which they are most likely to be seen. A shorter and more rounded head, as well as its small size (total length, including the tail, is under one metre) distinguishes it from the bulkier Smooth Otter (over 1.5 metres). In Tawau, it may be seen hunting in some river estuaries and mangroves along the coast. In all regions of S. And S.E. Asia where it occurs, populations are under threat due to pollution and/or habitat loss.
10.) Sunda Pangolin (Manis javanica) T
These are slow moving mammals, reaching up to 7kg in weight. The scales form protective armour and when disturbed, the scaly front legs may be used to protect the head or they may roll into a ball. The picture shows a female giving her offspring a characteristic ‘piggy back’. A long snout and tongue enables pangolins to consume large quantities of ants and termites, which they expose by using powerful claws to rip open nests.
In Borneo they have been recorded in many terrestrial habitats, from palm oil plantations, primary, disturbed and montane forests, peat swamps and sometimes in urban areas; it is not strictly aquatic but can swim. There are 8 species of pangolin in the world, 4 in Asia, 4 in Sub-Saharan Africa and all of them are threatened by habitat loss but poaching to supply the indefensible use of their scales in traditional medicines is the main reason for dramatic population declines.
11.) Sunda Slow Loris (Nycticebus coucang) T
The slow loris shown below exhibits the typical reddish eye shine produced as its eyes reflect back torchlight when picked out at night. As a primate, it has eyes on the front of the face and it easy to imagine how it is using its primate’s grasping hands and feet to move through the trees. Slow lorises are nocturnal, usually feeding in the canopy on an omnivore’s diet of fruit, insects and other small animals. They are the only primate to secrete venomous oil from a pair of brachial glands (on the elbow), smearing it on their fur after mixing it with saliva to activate it; the venom may protect against leeches, ectoparasites and even deter larger predators from catching them. They are able to lick the brachial gland to produce a toxic bite.
There are 5 species in Borneo, being distinguished largely by fur colour and face patterns; as their name suggests, they move slowly and steadily through the canopy. Populations of all species are under severe threat in Borneo mainly due to poaching to supply the misguided demand for these animals as pets.
12.) Hose’s Pigmy Shrew (Suncus hosei) T
Below is a picture of one of the world’s smallest mammals, the scale showing a total body length of 8cm (2.5cm tail, 5.5cm head +body); a typical adult weight is 2g. Being so small and nocturnal makes it very difficult to see; a preferred method to find it is by pitfall trap but, in this case, the shrew drowned before the trap was checked. Shrews are active hunters that mainly feed on insects and this species is found in lowland dipterocarp forests where infrequent sightings may cause underestimation of its numbers.
It is endemic to Borneo but a commoner, close relative, Savi’s Pigmy Shrew, is found throughout most of Asia and even limited parts of Africa and Europe. The size, nocturnal habits and habitat of Borneo’s pygmy shrews means that so much is still waiting to be discovered about their biology.
13.) Tufted Ground Squirrel (Rheithrosciurus macrotis) T
This picture captures the dynamism of this wonderful squirrel and shows some key features: the large, bushy tail held curved over its back, the tufted ears and the dark stripe along its light flanks.
An adult may be over 400cm (head + body) in length with a 300+cm tail. Here, it is on the ground but they can also be seen feeding in the canopy. This species is typically found in hill forest, not lowland rainforest; it is unusual to spot this squirrel repeatedly in the same patch of forest, suggesting that it may not stay in a defined territory but instead be continually on the move to search for trees producing its preferred fruit and nuts. The fragmentation of much of Borneo’s forests has resulted in this endemic squirrel becoming increasingly rare as this nomadic behaviour is disrupted.
14.) Binturong (Arctictis binturong) T
The Binturong is one of 9 species of civet in Borneo, and is found elsewhere in SE Asia, including Western Malaysia. It has a broad, prehensile tail, which, by grasping branches, enables it to move confidently in the canopy. Although carnivorous, most civets are also fruit-loving, in the case of the binturong, being fond of strangler fig fruit. The picture shows it to be a hairy, black civet with white-edged ears that are tufted and silvery parts of the face. The civets of Borneo are mainly nocturnal, a factor that contributes to the difficulty of spotting them.
Although the binturong is uncommon, Hose’s Civet (Hemigalus hosei), pictured above, is still more elusive. No hand-held camera photographs have been recorded of this endemic species; instead the camera trap image above captures one on the forest floor, showing a more slender and agile civet than the binturong. Obtaining better sightings of Hose’s Civet remains a challenge for Borneo mammal-watchers.
15.) Red-Cheeked Flying Squirrel (Petaurista petaurista) G
This dramatic picture shows the characteristic flying squirrel patagium, flaps of skin stretching between the outstretched limbs, which enable them to glide from tree to tree. As with a flying snake or lizard, a ‘flying squirrel’ is incorrect scientifically since no muscular effort is involved in their aerial locomotion. The long tail stretched out behind is free from the patagium, and perhaps works like a rudder. Borneo is a ‘hot spot’ for these animals, with 14 recorded species of which 7 have been seen in Tawau Hills alone.
The species shown here is one of Borneo’s 2 commonest: the Red-Cheeked, the other being Horsefield’s. Whilst it is known that these squirrels are mainly nocturnal and nest in tree holes, so much more is waiting to be learnt, for example about feeding habits, distribution and abundance.
Do you want to learn more about Borneo’s mammals?
Recommended reading
Phillipps, Q. And Phillipps, K. (2019) Phillipps’ Field Guide to The Mammals of Borneo and Their Ecology. Second Edition. Publishers: John Beaufoy Publishing
(An interesting and innovative field guide with anecdotes and incidental information.)
Payne, J. and Francis, C.M. (1998) A Field Guide to The Mammals of Borneo. First Edition. Publishers: The Sabah Society.
(For a long time, the established field guide but still an important reference book.)
Cheema, S. (2020) A Pocket Guide to Mammals of Borneo. First Edition. Publishers: OneStopBorneoWildlife Travel and Tour Sdn Bhd.
(An up to date, pocket-sized book giving an introduction to key mammal species.)
With thanks to Adi & Mala for the photograph of the Marbled Cat.
All other photographs in this article were taken by Shavez Cheema or Chun Xing Wong of 1StopBorneoWildlife.