Wild animals of Khao Yai

The largest land mammal in Asia. Khao Yai holds more than 400 individuals. Almost daily presence along forest edges and grasslands. Reproduction: about 22-month gestation for a single calf, females giving birth only every 4 to 6 years. Diet: large herbivore feeding on tall grasses, bamboo, young shoots, fallen fruits and bark over long nightly movements.

Gregarious, lives in matriarchal herds. Mainly active at dawn and dusk. Avoids areas with intense human presence.

Cool season (Nov–Feb): best period. Key areas: Pha Diao Dai and Mo Singto grasslands.

Endangered (IUCN)

Khao Yai is one of the few places in the world where the white-handed gibbon lives alongside the pileated gibbon, with natural hybrids documented by researchers. Arboreal primate whose dawn song is one of the most memorable soundscapes of Khao Yai. Local population still well represented in primary forest blocks. Reproduction: monogamous pairs, one infant every 2–3 years, with a long learning period alongside the parents. Diet: mainly frugivorous (figs, forest fruits) complemented by young leaves, flowers and occasional insects.

Lives in family groups. Moves by brachiation in the canopy. Territory defended through morning vocalisations.

Audible from around 5:30 am. Visible at forest edges in the morning. Regular all year round.

Endangered (IUCN)

Range limited to south-east Thailand, Cambodia and southern Laos. Striking black-and-white contrast in adult males. Khao Yai lies at the edge of its range: one of the rare contact zones with the white-handed gibbon, where mixed pairs and natural hybrids are observed. Reproduction: small family groups, one infant every 2–3 years. Diet: mainly forest fruits, young leaves, flower buds and occasional insects.

Performs duet songs with the female. Occupies the high canopy of primary forest.

Especially in the northern and central parts of the park. Best window: 6–9 am.

Endangered (IUCN)

The largest wild bovine in the world. Impressive silhouette with a characteristic shoulder hump. Reproduction: a single calf per female, staying protected within the herd for long periods. Diet: large herbivore grazing tall grasses, young shoots, shrub leaves and sometimes bark.

Herds of 8–40 individuals. Grazes in grasslands, retreats to forest during the day. Shy but can be dangerous if cornered.

Grasslands and forest edges at dawn and dusk. Night safaris are effective.

Vulnerable (IUCN)

Large deer and main prey of Southeast Asia's large predators. Very common in Khao Yai. Reproduction: one fawn per birth. Diet: opportunistic herbivore feeding on grasses, leaves, buds and aquatic plants.

Solitary or in small groups. Active at dawn and dusk. Frequently visits waterholes at night.

Grasslands and roadsides. Extremely regular on night safaris.

Vulnerable (IUCN)

The largest squirrel in Asia. Body length up to 35 cm with striking bicoloured fur. Reproduction: nests high in large trees, one small litter per year. Diet: eats big fruits, nuts, hard seeds, young leaves and sometimes bark.

Strictly arboreal. Performs spectacular leaps between trees. Often solitary and noisy.

Canopy of dense forest. Usually heard before being seen. Frequent year-round.

Near Threatened (IUCN)

Easily recognised by the pale crescent on its chest. Present in Khao Yai but elusive. Reproduction: one or two cubs per litter; young stay with the mother for a long period. Diet: omnivore feeding on forest fruits, insects, honey, roots and occasionally small vertebrates.

Mainly nocturnal. Eats large quantities of fruits and insects. Capable climber.

Dense forest zones. Tracks more common than actual sightings.

Vulnerable (IUCN)

Species absent from recent records. No resident population confirmed in Khao Yai since the late 1990s. Historical presence documented; the Dong Phayayen–Khao Yai complex remains a potential habitat monitored by the DNP. IUCN status: Endangered.

Solitary with huge territories. Mostly nocturnal. Avoids human contact.

Direct sighting is extremely unlikely. Its presence is a key indicator of ecosystem health.

Endangered (IUCN)

Large rodent covered in quills up to 30 cm long. Common but strictly nocturnal, regularly seen on safaris. Reproduction: one to two litters per year, reared in burrows. Diet: burrowing omnivore that eats roots, tubers, fallen fruits and seeds.

Strictly nocturnal. Forages on the ground and uses burrows.

Night safaris by vehicle: very frequent along roads and forest edges.

Least Concern

The only mammal entirely covered with keratin scales. Critically endangered due to poaching. Reproduction: a single well-developed young carried on the mother’s back. Diet: specialist feeder on ants and termites.

Nocturnal and solitary. Rolls into a tight ball when threatened.

Exceptionally observed. A few encounters documented since 2005.

Critically Endangered (IUCN)

The largest hornbill in Asia. Massive casque on the bill. Flagship bird of Khao Yai. Reproduction: the female is sealed inside a tree cavity and fed by the male. Diet: mainly fruits, supplemented with insects and small vertebrates.

Pairs or small groups. Nests in cavities of giant trees.

Flight easily recognisable by the loud whooshing of wings. Common in dense forest year-round.

Vulnerable (IUCN)

Hornbill with a ridged and colourful casque. Regularly observed in Khao Yai. Reproduction: female sealed into the nest cavity. Diet: mainly frugivorous, dispersing seeds over long distances.

Gregarious outside breeding season. Frugivore and key seed disperser.

Primary forest canopy. Common all year. Easy to locate by flight and calls.

Vulnerable (IUCN)

The most common hornbill in the park. Pale yellow bill with black casque. Reproduction: female sealed inside tree cavity. Diet: fruits, insects and small reptiles.

Adaptable, often near forest edges. More tolerant of human presence.

Observable almost everywhere in the park. Ideal starter species for beginners.

Least Concern

Large ground cuckoo with glossy black plumage and vivid rufous wings. Deep repetitive song is highly characteristic. Reproduction: ball-shaped nest in dense vegetation. Diet: predator of insects, lizards and small snakes.

Often walks on the ground or in low vegetation along forest edges.

Forest edge and roadside habitats. Song easily heard at dawn.

Least Concern

Small passerine with glossy black-bronze plumage. Spectacular aerial acrobat. Reproduction: small cup nest on branches. Diet: insectivore catching prey in flight from perches.

Sallies out from perches to catch flying insects. Territorial.

Perches along forest edges and inside forest. Easy to observe all year.

Least Concern

Wild ancestor of all domestic chickens. Its crow announces dawn in the jungle. Reproduction: well-hidden ground nest, eggs incubated by the female. Diet: omnivore pecking seeds, insects and small invertebrates.

Small family groups. Scratches forest floor for seeds and insects.

Forest edges and grassy clearings. Regular in mornings and late afternoons.

Least Concern

Ground-dwelling bird with dazzling turquoise, black and white plumage. Highly sought-after by birders. Reproduction: low, well-camouflaged nest on the forest floor. Diet: hunts insects, worms and small invertebrates on the ground.

Secretive, moves quietly across the forest floor in dense undergrowth. Fluted melancholic song.

Understory of primary humid forest. Difficult to see but song is recognisable.

Least Concern

One of the largest lizards in the world, exceeding 2 metres in length. Common near water bodies. Reproduction: lays eggs in burrows or termite mounds. Diet: opportunistic, taking fish, eggs, carrion and small mammals.

Excellent swimmer. Forked tongue constantly sampling the air.

Riverbanks, lakes and canals. Almost daily observations.

Least Concern

Bright green agamid lizard with a prominent dorsal crest. Strongly dinosaur-like appearance and very photogenic. Reproduction: lays eggs in soft soil. Diet: insectivorous and opportunistic carnivore.

Semi-arboreal, perches on branches overhanging streams. Dives into water when alarmed.

Streams, waterfalls and forest rivers. Very regular along shaded watercourses.

Least Concern

The longest venomous snake in the world (up to 5.5 m). Present in Khao Yai. Reproduction: builds a nest of leaves; the female may guard the eggs. Diet: feeds almost exclusively on other snakes.

Solitary and mostly diurnal. Avoids human contact.

Dense forest and edges. Never approach or disturb.

Vulnerable (IUCN)

The longest snake species in the world. Some individuals exceed 6 metres. Non-venomous constrictor. Reproduction: female coils around eggs for incubation. Diet: rodents, birds, monitors and civets by ambush.

Nocturnal and semi-aquatic. Lies in ambush near water.

Water edges at night. Occasionally seen during night safaris.

Least Concern

Large gecko with a powerful, resonant call (“to-kay!”). Orange spots on blue-grey background. Very common. Reproduction: lays a few eggs glued to the substrate. Diet: strictly insectivorous, hunting under lights.

Strictly nocturnal. Its call can be heard tens of metres away.

After dark, under outdoor lights. Almost impossible to miss.

Least Concern

Brown, stocky toad with prominent black parotid glands. Extremely common. Reproduction: long strings of eggs laid in ponds during the rainy season. Diet: nocturnal insect-eater.

Nocturnal, attracted to light to hunt insects. Toxic if ingested.

Ubiquitous at night around lodges, paths and forest edges.

Least Concern

One of the largest frogs in Southeast Asia, weighing up to 500 g. Reproduction: eggs laid in calmer stretches; tadpoles cling to rocks. Diet: insects, small crustaceans and worms.

Semi-aquatic, stays close to fast-flowing streams. Nocturnal.

Waterfalls and forest torrents. More vocal during the rainy season.

Near Threatened (IUCN)

Responsible for the spectacular evening bat flight near Khao Yai. Millions of individuals spiral out of a cave at sunset. Reproduction: one pup per female per year. Diet: specialist insectivore consuming huge numbers of moths.

Colony of several million individuals. Emerges in a tight spiral at dusk.

Wat Tham Phra bat cave at sunset. Unmissable spectacle.

Least Concern

Small frugivorous bat, important seed disperser in tropical forests. Reproduction: one or two litters per year. Diet: fruits such as wild mangoes, figs, bananas and nectar-rich flowers.

Nocturnal, feeds on fruits and nectar. Roosts in dense vegetation.

Visible at dawn and dusk along forest edges and in gardens.

Least Concern

Large black scorpion reaching over 12 cm. Impressive but generally of moderate medical concern. Reproduction: female carries the young on her back after hatching. Diet: carnivorous, eating insects, centipedes and other arthropods.

Nocturnal, hides under rocks and debris during the day.

Night safaris with UV light: fluoresces bright green in the dark.

Not evaluated

One of the largest tarantulas in Southeast Asia. Ground-dwelling species digging deep burrows. Reproduction: female guards the young in a cocoon at the bottom of the burrow. Diet: insects, centipedes and small lizards.

Nocturnal and solitary. Rarely leaves its burrow except at night.

Burrow entrances visible along trails. At night, individuals can be seen at the burrow mouth.

Not evaluated

Present in humid forest, especially during the rainy season. Reproduction: hermaphrodites depositing cocoons in saturated soil. Diet: blood of mammals, birds or reptiles.

Move on vegetation and are attracted by body warmth and vibrations. Bite is painless.

Rainy season (June–October): almost unavoidable. Gaiters are recommended.

Not evaluated

Myriapod reaching up to 30 cm. Active, venomous predator. Bite is very painful. Reproduction: female coils around the eggs until hatching. Diet: insects, other myriapods and spiders.

Nocturnal, hides under rocks and bark during the day. Extremely fast.

At night under debris on the forest floor. Never handle.

Not evaluated