Wednesday 29 December 2021

Tracking the feeding habits of Dholes in the Ujung Kulon National Park, southwestern Java.

Dholes, or Asian Wild Dogs, Cuon alpinus, were once found across a wide swath of South, Central, East, and Southeast Asia, from Bangladesh, Bhutan, India, Nepal, and Pakistan north to Kazakhstan, and east to China, the Korean Peninsula, and the Russian Far East, and south to Cambodia, Laos, Malaysia, Myanmar, Thailand, Vietnam, and the Indonesian islands of Java and Sumatra. However, habitat fragmentation across this range has badly impacted the species, and Dholes are now thought to occupy less than 25% of their former range, and are considered to be Endangered under the terms of the International Union for the Conservation of Nature’s Red List of Threatened Species.

In Indonesia Dholes are protected by law, and are thought to have a widespread but fragmented distribution. A limited number of studies have been carried out on the distribution and habits of Dholes, and while potential prey species have been identified in two national parks where they are known to occur (Baluran National Park and Ujung Kulon National Park, both on the island of Java), but direct evidence of prey selection or feeding has been sparse.

In a paper published in the Journal of Threatened Taxa on 26 December 2021, Dede Aulia Rahman of the Department of Forest Resources Conservation and Ecotourism at Bogor Agricultural University, and Mochamad Syamsudin, Asep Yayus Firdaus, Herry Trisna Afriandi, and Anggodo of the Ujung Kulon National Park, present the results of a camera-trap experiment intended to reveal the hunting preferences of Dholes in the Ujung Kulon National Park.

Rahman et al. divided the park into 329 one kilometre square grid sections, and placed camera traps in 108 of these, positioned so that each was at least 300-500 m from the next. These were left in place from January to December 2013, being checked every 28-30 days to ensure they were functioning, and repositioning if they had sighted no Animals after two or three checks.

The first Dhole predation event was recorded on 28 May 2013, when a pack of 15 adult Dholes was seen to attack a Banteng, Bos javanicus, calf, which was accompanied by three adult females, between 7.43 and 7.57 am. 

Photographs of predation on a young Banteng by a pack of Dholes on 28 May 2013: (1) A Dhole bites the neck of a young Banteng. (2)–(4) An adult female Banteng tries to protect the young Banteng. (5) Several members of the Dhole pack try to separate the young Banteng from an adult female Banteng. (6)–(7) Dholes kill a young Banteng on the far side of picture. (8) Adult female Bantengs come back to try and save the young Banteng. (9) The process of predation by Dholes is complete which is marked by several pack members resting. Rahman et al. (2021).

A second predation attempt was recorded on 24 September 2013, between 5.00 and 5.12 pm, when a group of six adult Dholes attempted to predate another young Banteng, again accompanied by three adult females.

Photographs of predation on a young Banteng by a pack of Dholes on 24 September 2013: (1) Young Banteng accompanied by three adult females. (2) One individual Dhole starts attacking the Banteng. (3)–(5) An adult female Banteng tries to protect the young Banteng. (6)–(8) Three Dholes are moving forward and attacking Banteng on the far side of picture. (9) Another individual Dhole running moving forward on the same side. Rahman et al. (2021).

In addition to these attacks on Bateng, five adult Dhole were observed chasing a Java Mouse-deer, Tragulus javanicus, on 18 April 2013, two adult Dholes were seen attacking a Wild Pig on 15 October 2013, and three adult Dholes were observed following an adult male Javan Rhinoceros, Rhinoceros sondaicus, on 31 July 2013.

(1)–(3) a Java Mouse-deer being chased by five adult Dholes. (4)–(6) Wild Pig attacked by two adult Dholes. (7)–(9) An adult male Javan Rhinoceros followed by three Dholes. Rahman et al. (2021).

The captured images show clear evidence of Dholes targeting Banteng, a type of wild Cattle, in the Ujung Kulon National Park. Although they appear to specialise in taking young members of the herd, Bateng might at first seem like quite a large prey item for a small Canid, but this is not out of keeping with the prey preferences observed for the species elsewhere. In India Dholes have been shown to mostly predate Chital Deer, Axis axis, and Sambar Deer, Rusa unicolor, both medium sized Deer, but will occasionaly hunt Gaur, Bos gaurus, the largest extant Bovid species. In Cambodia, Dholes primarily hunt Muntjac Deer, Muntiacus spp., but alto hunt Banteng, which make up about 18% of their diet. Finally, analysis of droppings left by Dholes in the Baluran National Park, East Java, has suggested that their diet there included Banteng and Water Buffalo, Bubalus bubalis.

Dholes are variable in their approach to hunting, and will hunt on their own, in pairs, or in packs of varying size, with larger groups tending to tackle larger prey. This is roughly in line with Rahman et al.'s findings, with one attack on a Bantang being carried out by 15 Dholes. However, observed hunts by Dholes on Cattle and other large prey in other areas have typically involved the pack attempting to spook and then chase the herd, separating calves from the adults in the confusion, whereas both attacks observed in the Ujung Kulon National Park began with a direct attack on calves that were close to adults.

Rahman et al. do not believe that the Dholes observed following a Rhinoceros were engaged in a hunting attmept, reasoning that at 1000-2000 kg such an Animal is likely to be considerably outside of their range, and that a group of three is probably to small would be too small for the attmept if they were to make it. Rather, they suggest, the Dholes may have been escorting the Rhinoceros away from a den site in order to ensure the safety of their young.

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