The Carnivore Community in a Dry Tropical Forest Mosaic in Huai Kha Khaeng Wildlife Sanctuary, Thailand

1. What they did

Little was known about the carnivore communities of south-east Asia. Between 1987 and 1989, the authors surveyed which carnivores lived in a 100 km² patch of dry tropical forest around Khao Nang Rum Research Station in Huai Kha Khaeng Wildlife Sanctuary, Thailand, and what they ate.

• Which carnivores were there. They used box traps set along roads and trails where carnivore spoor had been seen, their own sightings and those of workers, and identification of spoor. They regularly walked roads, trails and waterways to collect and record faeces, scrapes and tracks.
• What they ate. They identified hair in the faeces by eye or under the microscope against a reference collection of skins, and other remains such as rodent jaws and teeth, pangolin, lizard and snake scales, hog badger claws, primate nails, barking deer hooves, feathers, and crab and insect shells.
• Large and small carnivores. Because most faeces could not be assigned to one species, they sorted them by size: 2 cm or more across for large carnivores, under 2 cm for small carnivores (under 10 kg).
• Comparison. Faeces and sightings from other parts of the sanctuary were compared with those from the study area.

2. What they found

The carnivores

• 21 carnivore species from five families lived in the study area, and five more were recorded in nearby parts of the sanctuary.
• Spoor and sightings of large cats, mostly leopards, were the most common evidence of larger carnivores. Capture and tracking (from the first author’s earlier study) showed four resident leopards (three spotted, one black) and one resident tiger.
• Dholes left less evidence than the large cats, but sightings suggested at least twice the leopard density. They were seen six times, mostly alone, once as a pair, and once as a pack of “about ten” feeding on a sambar deer.
• Signs of the Malayan sun bear were seen more often than of the Asiatic black bear, which was reported only once. Both bears seemed uncommon.
• The Asian golden cat and clouded leopard were each seen only once, but tracks showed at least one medium-sized cat regularly using roads and trails.
• Leopard cats, Asiatic jackals and some civets were the small carnivores most often seen, or whose spoor was most often seen, along roads and trails.
• A latrine site, believed to be from the small-clawed otter, held faeces containing only crab remains.

Large carnivore diet (438 faeces)

• Barking deer made up 44% of identified prey.
• Macaques, sambar deer, wild boar, crestless Himalayan porcupine and hog badger together made up 31.3%.
• Faeces from other parts of the sanctuary showed similar preferences.
• Tigers and leopards were seen feeding on a banteng killed by hunters, and tiger and leopard tracks showed feeding at a gaur carcass, yet neither species was found in faeces.
• 63% of large carnivore faeces in the study area, and 84% outside it, were known to be from large cats, mainly leopards.

Small carnivore diet (657 faeces)

• Murid rodents made up 33% of identified prey. The yellow rajah rat and the bay bamboo rat together made up 22.4%.
• Non-mammal prey made up 21.3%, over half of it lizards and insects.
• Seeds from edible fruits made up 12.4% of food items. At least 10% of small carnivore faeces were known to be from civets.

3. What they concluded

• The diverse carnivore community reflects an abundant and diverse prey community, with prey in a range of size classes.
• Barking deer may be eaten more than other hoofed animals because leopards, which left most of the large faeces, prefer prey under 50 kg. Sambar, gaur and banteng are larger and less common, and wild boar were sparse, partly because illegal hunters targeted them.
• Large meals from big carcasses may leave few identifiable remains in faeces, which could explain the missing gaur and banteng and part of the “unknown” category.
• Collecting faeces along roads and trails biases the results toward carnivores that use those routes, especially for large carnivores.
• Some large prey in small carnivore faeces may come from jackals and civets scavenging large carnivore kills.
• Mostly solitary dholes may point to a diet with many small prey and smaller home ranges.
• The forest mosaic allows open-woodland and dense-forest species to live side by side, but its patchiness may restrict small, specialized species. Leopards outnumbered tigers in the study area, the reverse of other parts of the sanctuary, because leopards can use trees, survive on smaller prey, hunt in burnt and regrowing areas, and need less water.

4. How tracking was or was not used

Spoor identification was one of three ways the authors assessed which carnivores were present and how common they were. They walked roads, trails and waterways to record faeces, scrapes and tracks, and set box traps where carnivore spoor had been seen. Tracks were the evidence for a medium-sized cat using roads and trails, for tiger and leopard feeding at a gaur carcass, and (as “observed evidence”) for the tiger, sun bear and small-clawed otter in the species list. Faeces were assigned to large or small carnivores by diameter. Earlier “capture and tracking” of the large cats is cited from Rabinowitz (1989); the paper does not say what kind of tracking that was.

5. Tracker or observer certification

Not reported. The paper does not say who identified the spoor and faeces. Field assistants are thanked by name, and some species records rest on sightings by workers.

6. Other technologies, skills or innovations

• Microscopic hair comparison against a reference collection of skins at the National Research Council of Thailand.
• Identification of other remains in faeces (teeth, scales, claws, nails, hooves, feathers, shells) using museum specimens, keys and distribution maps.

7. Implications for conservation (from the paper)

• Carnivores are often more severely affected than other animals as parks become smaller and more heavily used, so understanding carnivore communities is essential for tropical forest management and conservation.
• Carnivores are among the most wide-ranging and specialized members of the wildlife community, yet among the least understood. Detailed knowledge of the carnivore community is critical for a balanced, long-term forest management policy for any protected area.