What do sun bears eat?
Sun bears (Helarctos malayanus) are omnivorous opportunists whose annual diet across Borneo, Sumatra, and the Malay Peninsula is built on two pillars: social insects, especially termites of the genera Macrotermes and Coptotermes and ants of the genera Oecophylla and Camponotus, and fleshy tropical fruit, dominated by figs (Ficus spp.) and seasonally by durian (Durio spp.). Honey from stingless Trigona bees and giant Apis dorsata combs adds a high-density calorie pulse, while earthworms, beetle larvae, the occasional bird, egg, or small rodent, and rare carrion fill out the menu. The species' 20 to 25 cm protrusible tongue and 10 cm curved claws are evolutionary tools shaped almost entirely by this insect-and-honey diet.
A Bear Built Like an Anteater With Climbing Gear
Walk a transect through dipterocarp forest in the Danum Valley of Sabah, Malaysian Borneo, in the dry season. The understorey is open, the canopy is fifty metres up, and the soil is laced with termite galleries the size of a fist. A sun bear has been working a strangler fig along this slope for the past hour. The bark on the trunk is shredded to chest height, the leaf litter is overturned in a one-metre arc around the base, and three flattened weaver ant nests sit beside the path. The bear has eaten figs, ants, termites, and a mouthful of palm rachis pith in roughly that order, and will probably continue feeding until dusk before climbing eight metres into a Lithocarpus to sleep.
That image, which any of the field biologists who have followed wild sun bears will recognise, is the daily reality of the smallest bear on Earth. The species does not hunt large prey. It does not patrol territories defending a cache. It walks, sniffs, climbs, digs, and tongues its way through a tropical forest, eating whatever the forest happens to be offering on that day. For the broader natural history and conservation status of the species, see our anchor profile of the sun bear.
"If you ask me to summarise sun bear feeding ecology in a single sentence, I would say this: they are myrmecophages who happen to eat fruit, and frugivores who happen to eat ants. The two halves of the diet are inseparable, and you cannot understand one without the other."
-- Gabriella Fredriksson, Sumatran Orangutan Conservation Programme, two decades of sun bear field research in East Kalimantan
The Two Halves: Insects and Fruit
Across every published scat-analysis study from Sabah to Sumatra to the Malay Peninsula, two food categories dominate the sun bear menu: social insects and fleshy fruit. The relative proportions shift with the calendar and with the eight-year mast cycles of dipterocarp forests, but the underlying split is remarkably stable.
Mean Annual Diet Composition (Sun Bear, Lowland Borneo and Sumatra)
| Food Category | Share of Annual Diet (Scat Frequency) | Peak Season |
|---|---|---|
| Termites (Macrotermes, Coptotermes, Nasutitermes) | 35 to 50% | Year-round, peak in dry transitions |
| Figs (Ficus spp., over 30 species used) | 15 to 30% | Year-round, asynchronous fruiting |
| Ants (Oecophylla, Camponotus, Polyrhachis) | 10 to 20% | Year-round |
| Beetle larvae (Cerambycidae, Scarabaeidae) | 5 to 15% | Year-round |
| Honey and bee brood (Trigona, Apis dorsata) | 3 to 10% | Year-round, peak after flowering |
| Mast fruits (durian, dipterocarp drupes, oaks) | 0 to 40% (highly cyclical) | Mast years only, every 4 to 7 years |
| Other fruit (mangosteen, langsat, rambutan, palm) | 5 to 15% | Localised, seasonal |
| Earthworms | 2 to 8% | Wet season |
| Birds, eggs, small mammals, lizards | <5% | Opportunistic |
| Carrion | <1% | Rare |
The first thing a reader unfamiliar with the species notices in this table is that meat is essentially absent. The sun bear is the most insectivorous and frugivorous of all bears, more so than the spectacled bear of the Andes and far more so than the giant panda, whose bamboo specialisation pulls its diet in a different direction entirely. For comparison with another tropical-forest bear, see what do spectacled bears eat, and for the most extreme dietary specialist in the family, see what do pandas do all day.
"We analysed 1,141 sun bear scats from Sungai Wain Protection Forest in East Kalimantan over six years. Termites occurred in 87 percent of samples. Figs occurred in 41 percent. Vertebrate remains occurred in fewer than 4 percent. The data tell a clear story: this is a bear whose stomach is full of insects most days of its life."
-- Gabriella Fredriksson and colleagues, Mammalian Biology (DOI 10.1016/j.mambio.2005.10.002)
Honey: Why the Sun Bear Is Called Beruang Madu
The Malay name for the species is beruang madu, the honey bear, and the bear has carried that label across English-language natural history writing for two centuries. It is a name earned by behaviour. Sun bears do eat honey, and they eat it from two very different bee groups, with two very different harvest strategies.
Stingless Bees: The Year-Round Larder
Stingless bees of the genus Trigona and its relatives nest inside tree cavities, often in mature hardwoods such as Koompassia and Shorea. Each colony stores small honey pots and a brood comb in a defended chamber accessed by a single waxy entrance tube. Sun bears locate these colonies by smell, climb to the entrance, and excavate the cavity with claws and teeth until the chamber is exposed. The reward per colony is modest, perhaps a few hundred grams of honey and brood, but the bees do not sting, the colonies are widely distributed, and a bear can raid five to ten in a single afternoon. Field cameras at Trigona trees in Sabah and Sarawak have repeatedly recorded the same individual bears returning to the same trees for weeks until the colony collapses or relocates.
Giant Honey Bees: The High-Risk Jackpot
Apis dorsata, the giant honey bee of Asia, builds large open combs hanging from the underside of high branches in emergent trees, particularly Koompassia excelsa and tall figs. A single comb can hold ten to twenty kilograms of honey and brood. The colonies are aggressive and inflict painful stings. Sun bears, with their loose neck skin, dense fur, and tolerance for pain, will climb thirty metres into the canopy, knock the comb loose with a swipe of the forepaw, and follow it down to feed. Stings to the muzzle and ears are visible afterwards but rarely cause lasting injury. For the anatomy that makes this honey-extraction lifestyle possible, see sun bear tongue: longest of any bear.
"I have watched sun bears at a single Apis dorsata tree in Borneo make eleven separate climbs in one night, each climb ending with a comb pulled to the ground and the bear feeding for twenty minutes before the next ascent. The bees were on the bear continuously. The bear did not seem to care."
-- Siew Te Wong, Bornean Sun Bear Conservation Centre, founder and CEO
Termites and Ants: The Daily Bread
If honey is the celebrated headline, termites and ants are the silent staple. Across the bulk of sun bear range, more than half of all feeding bouts and more than half of all scats by frequency contain termite or ant remains. The sun bear is the most committed myrmecophage in the bear family.
How a Sun Bear Eats a Termite Mound
A sun bear locates a termite colony by smell, often a mound or a galleried log, and goes to work with the front feet. The 10 cm claws function as ice axes, hooking into hardwood and prying it open along grain lines. Once a chamber is exposed, the bear collapses chest-first onto the substrate, places the muzzle into the breach, and uses the long protrusible tongue to lap up workers, soldiers, and brood in long sweeping strokes. Bouts can last forty minutes at a single mound. A captive feeding study at a sanctuary measured a single bear consuming roughly one kilogram of termite biomass per day during a sustained excavation period, which translates to tens of thousands of individual insects.
The Ant Hierarchy
- Weaver ants (Oecophylla smaragdina): live in folded-leaf nests in the canopy. Sun bears reach into the leaf bundle, crush the nest, and eat ants and brood together. The formic acid load is high, but the bear apparently tolerates it.
- Carpenter ants (Camponotus spp.): nest inside dead standing wood. The bear breaks the log open and tongues the galleries.
- Spiny ants (Polyrhachis spp.): nest at ground level under bark plates. Less calorie-dense per nest but very widespread.
The combined contribution of social insects to the sun bear diet, by mass and by encounter rate, exceeds that of any other food category in most studies. The species' role as an insectivore is structurally similar to that of a giant anteater on a different continent, achieved with bear anatomy rather than xenarthran anatomy.
Figs: The Forest's All-Year Fruit
Figs are the second pillar of the sun bear diet and the reason the species can survive in tropical forests where dipterocarp mast fruits are absent for years at a time. Over thirty species of Ficus are used by sun bears across the range, including strangler figs (Ficus benjamina, F. stupenda), free-standing figs (F. variegata), and ground-level rheophyte figs along streams.
The reason figs matter so much is asynchronous fruiting. Unlike most tropical fruit trees, which ripen in narrow seasonal pulses, fig trees in a given forest fruit on staggered individual schedules. At any given week of the year, somewhere in a sun bear's home range, at least one fig tree is in fruit. This makes figs a year-round insurance crop, and explains why fig stems show up in sun bear scat in every month sampled. Sun bears swallow the fruit whole, digest the soft tissue, and pass the seeds intact, which makes them effective dispersers of fig genetics across the forest.
For more on how habitat shapes this fruiting calendar, see where do sun bears live.
Mast Fruiting: Feast and Famine on a Six-Year Clock
Outside of figs, the dominant fruit pulse in dipterocarp forests of Southeast Asia is the general flowering, or masting, event. Triggered by El Nino dry spells and unusual cool nights, hundreds of dipterocarp species and many associated fruit trees, including some figs, durians, oaks, and lithocarps, synchronise their flowering across millions of hectares. The result is a brief, overwhelming pulse of fruit and seed availability roughly every four to seven years.
For sun bears, masting is the closest the tropics come to a temperate-zone fall mast. Bears travel further, feed on the ground for longer, switch from insects to fruit, and add body fat in measurable quantities. Between mast events, fruit availability collapses to whatever figs are bearing, and bears revert to a heavy reliance on termites, ants, and earthworms.
Sun Bear Diet by Mast Phase, Bornean Lowland Forest
| Phase | Approximate Years | Dominant Foods | Bear Body Condition |
|---|---|---|---|
| Mast year | Year 0 of cycle | Dipterocarp seeds, durian, oak acorns, mass figs | Peak fat, breeding spike |
| Post-mast | Years 1 to 2 | Figs, residual fallen seeds, termites | Stable |
| Inter-mast trough | Years 3 to 5 | Termites, ants, figs, earthworms | Lean, longest foraging hours |
| Pre-mast build | Year 6 | Figs, increasing flowering signals, insects | Variable |
The feast-famine pattern matters because it explains why sun bears are vulnerable to logging in ways that single-season studies miss. A logged forest that retains figs but loses mature dipterocarps may look adequate in an inter-mast year and inadequate during a mast event, and the bears that cannot find fat-building food during masting are the ones that fail to reproduce.
"The mast cycle is the heartbeat of sun bear ecology. You can study a bear for three years and never see one. Then a mast event hits, and the same animal you tracked walking 4 km a day on a termite diet is suddenly on the ground for 18 hours fattening on dipterocarp seed. Both modes are the same bear. Conservation that ignores either one will fail."
-- Roger McNeely, Ursus, on long-term sun bear movement and feeding studies in Sabah
Durian, Mangosteen, and the Other Tropical Fruits
Beyond figs and dipterocarp mast, sun bears eat a long list of named tropical fruits that overlap heavily with what humans value in the same forests. The dietary list includes:
- Durian (Durio spp.): The famously pungent thorny fruit. Sun bears climb the tree and feed on fallen ripe fruit, sometimes ripping open husks with claws. Local farmers in Sabah and Sumatra report sun bears as primary consumers of wild durian, sometimes in direct conflict with human harvest.
- Mangosteen (Garcinia mangostana and wild Garcinia spp.): Soft sweet fruit, eaten whole; seeds passed and dispersed.
- Langsat and rambutan (Lansium, Nephelium): Cluster fruits, both wild and cultivated forms used.
- Palm fruits: oil palm in disturbed habitats, but also wild rattan and Caryota fruit.
- Wild figs of secondary forest: especially around old logging roads where pioneer Ficus species establish quickly.
The crop overlap with humans is one of the leading drivers of human-bear conflict. A sun bear that has learned to feed on durian or oil palm fruit becomes a target for farmers, and the species is occasionally killed in retaliation, though direct attacks on people are rare. For more on the species' real-world threat profile, see are sun bears dangerous.
Earthworms, Grubs, and the Wet-Season Switch
During heavy monsoon rains, sun bear scat composition shifts measurably toward soft-bodied invertebrates. Earthworms become abundant on saturated forest floors, and bears appear to switch from termite excavation, which is harder on waterlogged substrates, to surface foraging on worms. Beetle grubs in rotting wood, especially Cerambycid (longhorn beetle) and Scarabaeid (rhinoceros beetle) larvae, are a constant year-round food but become a more visible component when bears are working logs in shaded wet forest. A single rotting Shorea log can yield several hundred grams of grub biomass in one feeding bout.
This wet-season substitution highlights the broader theme of the sun bear diet: substitutability. Termites, ants, earthworms, and grubs are nutritionally similar packages of insect protein and lipid, and the bear can swap among them as conditions favour each. The fruit half of the diet shows the same flexibility, with figs taking over when mast fails and mast taking over when it returns.
Vertebrates, Eggs, and the Rare Scavenge
Sun bears do eat vertebrates, but only in small numbers and only opportunistically. Documented prey items in scat and direct observation include:
- Ground-nesting bird chicks and eggs (junglefowl, partridges, pittas)
- Tree-nesting bird eggs reached during honey raids
- Forest rodents, including spiny rats and tree shrews
- Frogs and small lizards in stream margins
- Freshwater crabs in shaded creeks
- Fish in shallow pools, very rarely
True predation on larger vertebrates such as small ungulates, primates, or pangolins is essentially undocumented in wild sun bears. Scavenging on large carcasses is also rare. Tropical decomposition is fast, large carrion is uncommon outside of poaching events, and other scavengers, including tigers, dholes, clouded leopards, civets, and monitor lizards, typically reach a carcass first.
For an interesting comparison with the only other surviving non-temperate bear lineage, see spectacled bear, which evolved a similar omnivorous niche in the Andes with a sharper lean toward fruit and bromeliad hearts and almost no insect specialisation.
Anatomy of a Honey Specialist
Almost every distinctive feature of sun bear anatomy is explained by the diet described above.
| Trait | Measurement | Dietary Function |
|---|---|---|
| Tongue length | 20 to 25 cm, longest of any bear | Reaches deep into termite galleries and bee nests |
| Claws (forefeet) | Up to 10 cm, sharply curved | Tears bark, breaks rotten wood, climbs to canopy fruit |
| Body size | 27 to 80 kg, smallest extant bear | Allows climbing slender fruit tree branches |
| Skull and jaw | Robust, broad cheek teeth | Cracks hardwood and crushes tough fig and durian husks |
| Loose neck skin | Pronounced dewlap area | Tolerates bee stings and bites without injury |
| Olfactory acuity | Exceptional even by bear standards | Locates termite mounds and stingless bee colonies underground |
| Lifespan and reproductive timing | Delayed implantation, year-round food access | Cubs born during peak fruit periods |
The tongue is the most commented-on feature in popular natural history writing, and it deserves the attention. No other ursid has anything like it, and the closest analogue is found not in another bear but in mammals such as the giant anteater and the aardvark, which share the myrmecophage lifestyle. The convergence is a textbook example of how a tropical insect-and-honey diet shapes vertebrate anatomy.
For more on how cubs learn this complex foraging skill set from their mothers, see sun bear cubs and mothers. For the chest patch that researchers use to identify individual sun bears in field studies of feeding behaviour, see why do sun bears have chest markings.
Seed Dispersal: The Sun Bear as Forest Engineer
Beyond its own survival, the sun bear's diet has consequences for the forest itself. Two ecological services stand out.
Fig Dispersal
Sun bears swallow fig fruits whole and pass viable seeds in scat over distances of one to several kilometres from the parent tree. In forests where the largest frugivores, including orangutans and hornbills, have declined under hunting and habitat loss, sun bears become disproportionately important fig dispersers. Loss of sun bears from a forest fragment is followed by measurable reductions in fig recruitment, which then cascades into reductions in the dozens of vertebrate species that depend on figs as a year-round resource.
Durian and Hardwood Seed Dispersal
For larger-seeded fruits such as durian and some dipterocarp drupes, sun bears swallow or transport seeds short distances, with some passage through the gut and some simple drop and spit at feeding sites. The dispersal distances are smaller than for figs but still significant compared with no dispersal at all. Mast-year seed shadows in Bornean forests show measurable contributions from sun bear handling.
Nutrient Cycling
The act of breaking open termite mounds, ant nests, and rotten logs is itself an ecosystem service. By exposing the contents of these structures to other consumers and to decomposers, sun bears accelerate nutrient turnover in the forest floor in a way that no other large vertebrate in Southeast Asia matches.
What This Means for Conservation
The species' diet is the single best argument for why sun bear conservation has to focus on forest integrity rather than on isolated reserves of a single tree species or single habitat type. A sun bear needs:
- a year-round fig supply, which means mature fig trees of multiple species
- a working mast cycle, which means intact dipterocarp forest at landscape scale
- a healthy termite and ant fauna, which means undisturbed dead-wood structure
- enough connected habitat to walk between fruiting events without crossing open ground
Plantations, even when they retain bears for a few years through edge effects, do not provide the multi-decade fig and dipterocarp mosaic that sun bears require. The diet is, in effect, a window into what the forest itself needs to be in order to keep the species alive.
For comparable conservation pressures in another bear species, see the global picture in our anchor profile of the sun bear and the wider context of how bear diets respond to landscape change.
Comparing the Sun Bear Diet to Other Bears
A side-by-side reminder of how unusual the sun bear menu is compared with its better-known cousins. While other bears swing between meat and salmon and seal and berry, the sun bear remains anchored to insects and fruit across all seasons.
| Bear Species | Dominant Animal Food | Dominant Plant Food | Insect Specialisation |
|---|---|---|---|
| Sun bear | Termites, ants, bee brood | Figs, durian, mast fruits | Very high |
| Spectacled bear | Insects, small mammals | Bromeliads, palm hearts, fruit | Moderate |
| American black bear | Insects, fawns, salmon | Berries, acorns, beechnuts | Moderate |
| Brown bear | Salmon, ungulates, carrion | Berries, roots, herbaceous | Low |
| Polar bear | Seals, beluga, beached whales | Negligible | Negligible |
| Giant panda | Negligible | Bamboo (almost exclusively) | Negligible |
| Asiatic black bear | Insects, occasional vertebrates | Acorns, berries, fruit | Moderate |
| Sloth bear | Termites, ants (specialist) | Fruit, flowers, honey | Very high |
The sun bear shares its insect specialisation most closely with the sloth bear of the Indian subcontinent, which evolved an analogous suite of adaptations including missing front incisors and a vacuum-like feeding posture for termite mounds. Both species are evidence that the bear body plan can converge on an anteater-like niche when the climate stays warm enough that the alternative, hibernation, becomes unnecessary.
Reading and Reference
For further factual context and high-quality reading on related topics, the curated knowledge bases at Whats Your IQ, When Notes Fly, Evolang, and Pass4Sure are useful starting points across science, music, language, and professional learning. For tools to convert PDFs of academic papers and archival natural history monographs into searchable text, see File Converter Free.
Internally on Strange Animals, the closest thematic neighbours to this article are the sun bear anchor profile, the sun bear tongue anatomy piece, the geographic context in where do sun bears live, the safety overview in are sun bears dangerous, and the social and reproductive context in sun bear cubs and mothers and why do sun bears have chest markings.
References
- Fredriksson, G. M., Wich, S. A., and Trisno (2006). Frugivory in sun bears (Helarctos malayanus) is linked to El Nino-related fluctuations in fruiting phenology, East Kalimantan, Indonesia. Biological Journal of the Linnean Society, 89(3), 489-508. DOI: 10.1111/j.1095-8312.2006.00688.x
- Fredriksson, G. M., Danielsen, L. S., and Swenson, J. E. (2007). Impacts of El Nino related drought and forest fires on sun bear fruit resources in lowland dipterocarp forest of East Borneo. Biodiversity and Conservation, 16(6), 1823-1838. DOI: 10.1007/s10531-006-9075-0
- Wong, S. T., Servheen, C. W., and Ambu, L. (2004). Home range, movement and activity patterns, and bedding sites of Malayan sun bears (Helarctos malayanus) in the rainforest of Borneo. Biological Conservation, 119(2), 169-181. DOI: 10.1016/j.biocon.2003.10.029
- Wong, S. T., Servheen, C. W., Ambu, L., and Norhayati, A. (2005). Impacts of fruit production cycles on Malayan sun bears and bearded pigs in lowland tropical forest of Sabah, Malaysian Borneo. Journal of Tropical Ecology, 21(6), 627-639. DOI: 10.1017/S0266467405002622
- Te Wong, S., Servheen, C., and Ambu, L. (2002). Food habits of Malayan sun bears in lowland tropical forests of Borneo. Ursus, 13, 127-136. DOI: 10.2192/1537-6176(2002)013[0127:FHOMSB]2.0.CO;2
- Steinmetz, R., and Garshelis, D. L. (2010). Estimating ages of bear claw marks in Southeast Asian tropical forests as an aid to population monitoring. Ursus, 21(2), 143-153. DOI: 10.2192/09GR016.1
- Augeri, D. M. (2005). On the biogeographic ecology of the Malayan sun bear. Cambridge University Doctoral Thesis. DOI: 10.17863/CAM.16028
- Nakashima, Y., Inoue, E., Inoue-Murayama, M., and Sukor, J. R. A. (2010). Functional uniqueness of a small carnivore as seed dispersal agents: a case study of the common palm civets in the Tabin Wildlife Reserve, Sabah, Malaysia. Oecologia, 164(3), 721-730. DOI: 10.1007/s00442-010-1714-1