Report on Monkey Survey at Phana

Report on Monkey Survey at Phana

Research teams from Thailand: Prof. Dr. Suchinda Malaivijitnond

Primate Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand

Tel/Fax: 02-2185275


Mr. Sarawoot Gomuttapong (Graduate student)

Mr. Sarun Asawanuchit (Graduate student)

Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand

Research teams from Japan: Prof. Dr. Yuzuru Hamada

Evolutionary Morphology Section, Primate Research Institute, Kyoto University, Inuyama, Japan

Tel: +81-568-63-0521, Fax: (+81)-568-61-5775


Mr. Yahiro Kazuya (Undergraduate student)

Faculty of Liberal Arts, Kyoto University, Japan

Mr. Fujimoto Shunpei (Undergraduate student)

Faculty of Agriculture, Kyoto University, Japan

Mr. Mizutani Hiroki (Undergraduate student)

Faculty of Economy,Kyoto University,Japan

Ms. Okazaki Sachiko (Undergraduate student)

Laboratory of Veterinary Physiology, Department of Veterinary

Medicine, Faculty of Agriculture, Tokyo University of

Agriculture and Technology, Fuchu, Tokyo, Japan

Research Duration: September 8-9, 2011

The brief survey of monkeys at Phana was done by a research team, within a later half day of September 8 and a few hours in the morning of September 9, 2011, as a part of the International Symposium “Biodiversity and ecology of wildlife in Thailand”. This symposium was hosted by the Department of Biology, Faculty of Science, Chulalongkorn University, Thailand in collaboration with the Primate Research Institute of Kyoto University, Japan.

Monkeys at Phana District,  Amnat Charoen Province are Macaca fascicularis with common names of crab-eating macaques, cynomolgus macaques or long-tailed macaques. In Thailand, they are locally called by various names, such as “Ling Samae (“Ling” = monkey, Samae = name of crab at the mangrove forest)”, Ling Hang Yaow (Hang = tail, Yaow = long)” or “Ling Thep Pranom (which is based on the crest hair being like “Wai or Pranom”)”.

Generally, their distribution is from southern Bangladesh, eastward to Myanmar, Thailand, Laos and Vietnam, and southward to Malaysia, Singapore, Philippines, and Indonesia, including the Nicobar islands in India. In Thailand, their distribution is from the lower northern (latitude 16.30 °N, at Pichit and Nakhon Sawan Province) to the southernmost Thailand (latitude 6.15 °N, at Yala and Satun Province).

In each sex, they can be categorized into 4 age-classes as follows:

Adult female: fully mature female with huge body size, but smaller than adult male, big, red and long nipples, the sex skin is reddening or swelling during ovulation time.

Sub-adult female: female with intermediate body size, small, not very red and short nipples, the sex skin is reddening or swelling during ovulation time. At Phana, some sub-adult female showed the scotum-like swelling (Malaivijitnond et al., 2007).

Adult male: fully mature male monkeys with huge body size, fully grown canines and the testes fully descended into the scrotal sac.

Sub-adult male: male monkeys with intermediate body size, partially grown canines and the testes partially descended into the scrotal sac.

Juvenile: in male monkeys, small body size and the testes are in the abdominal cavity, not descended into the scrotum. In females, small body size and they do not have sex skin swelling and reddening. Both sexes usually stay together as a group.

Infant: baby monkey attaching or hanging with mother (age <1 year), small body size, many wrinkles and black hair on face, usually staying within a distance of 1 m from mother.

Don Chao Poo (Sacred forest) in Phana District, Amnat Charoen Province (N15O 36’36.4”, E104O 50’ 53.1”) is located in the distribution range of this species. A population of long-tailed macaques inhabiting Phana was first counted in October 2004. There were 3 groups of monkeys with 378 individuals counted, but we estimated that they should have about 600 monkeys (Malaivijitnond et al., 2011). The habitat of Phana monkeys is a patchy forest as we particularly found in many locations in Thailand. During this time of our visit, 3 groups and 464 individuals were counted (but we estimated that they should have more than 600 monkeys, because during the day of our survey it was slightly raining and many monkeys hid in the forest).

The macaque population is living in a good condition. No obese monkeys were found (which is regularly seen in many tourist attraction sites, such as Sarn Pra Karn, Lopburi Province). However, the population composition is biased to younger age classes; infants and juveniles are of  higher frequency and about 60% of adult females are lactating with infants. It means that the fecundity is high and the population high and  is increasing rapidly.

We could see many social activities between monkeys here, such as fighting between female monkeys, grooming (both autogrooming and allogroming), copulating, playing in juveniles, and foraging for foods.

As macaques tended to be found in the visitors’ place or on the road, they appear to depend on provisioning from humans. High calorie, but low quality, foods, such as potato chips, could lead to the population increase. Provisioning to macaques also raises other problems of injured monkeys. Provisioning on the road while humans are in the cars persuades monkeys to the road and has caused a bad habit of begging for food, and many monkeys got injured by traffic accidents. Several macaques are found with wounds remaining on their body, some are severe and some are light. Also, direct contact with monkeys can cause the bidirectional transmission of diseases between humans and monkeys, such as tuberculosis and simian viruses.

Phana monkeys have such a unique behavior of making tight aggregation of individuals, sometimes 20-40 individuals, which we have not seen in other groups of long-tailed macaques in Thailand. It usually occurs in monkeys living in a cold weather, such as in Japanese macaques.

The population is rather isolated from other populations of conspecifics, and thus the genetic heterogeneity is on the course of decreasing. The evidence indicating the low genetic variation (or inbreeding depression) in this group are a supernumerary nipple and light-coloured pelage. Provisioning would have driven the higher ranked lineage to increase in population more than the lower ranked. A monkey with a tumor was also observed.

Human – monkey conflicts are not yet severe, though it threatens to become severe as in Lopburi and Khao Wang Petchaburi in the future. Damage on humans (injury by biting and scratching, or falling down by threatening of monkeys), at houses (stealing food and damage on houses) or cars would occur. On the other hand the counter-measures such as catching and translocation of monkeys by humans would be taken.


Phana macaques and wildlife are the symbol of harmonic co-existence of life of humans and nature. Monkeys and wildlife are treasure of Phana. However, management is indispensable as they are under the influence of human impact. Recommendations for management are written as follows:

1. Control of population: The amount of provisioning should be controlled. Contraceptive protocol, which do not influence on the sex-hormone secretion, should be considered, such as tubule (of vas deferens) ligation in male monkeys. Population structure and lineage structure (kin groups in the troop) should be studied.

2. Provisioning should be made only inside park. Provisioning on or along road should be banned. Construction of bumps on the road to reduce speed of cars and to prevent traffic accident on monkeys.

Provisioning foods should be scattered in many points, then all monkeys can have access to the food, and the higher rank monkeys can’t monopolize food.

3. Human-monkey interactions and control of bidirectional transmission:

To prevent conflict becoming severe, the way of provisioning should be controlled. Direct contact between humans and monkeys should be kept minimal. Instruction to visitors for the way of contact with monkeys, such as not to look at monkey’s eyes, which means threatening monkeys and monkeys will counter attack to that person.

To prevent zoonosis and humanosis, transmission of diseases to and from monkeys, the way of contact, including the way of provisioning and watching monkeys should be instructed.

Drinking water for monkeys without contamination should be installed, because nowadays the monkeys drink dirty (contaminated with pathogens) water.

Keep clean the provisioning site.

Fruit trees should be planted for monkeys to eat.

1. Malaivijitnond S, Hamada Y, Suryobroto B, Takenaka O. 2007. Female long-tailed macaques with scrotum-like structure. American Journal of Primatology. 69 (7):721-735.

2. Malaivijitnond S, Vazquez Y, Hamada Y. 2011. Human impact on long-tailed macaques in Thailand. (In Managing Commensalism in Long-tailed macaques, Lisa Jones-Engel, Michael Gumert, Augustin Fuentes, eds).CambridgeUniversityPress,UK. Pp. 120-160.


We would like to thank the Primate Research Institute, Kyoto University, Japan and the Primate Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University for the grant support. We are grateful for the warm welcome and hospitality of Phana people while we visited there, especially to Khun Prachoenlarp Intarachan and Khun Surachet Thongphum for all arrangements, help and support. We also sincerely thank Khun Lawrence Whiting and Ajarn Pensri Whiting for accommodation and arrangement for our team members, and especially for introducing this project to us.

About isantraveller

I have been in and around North-East Thailand for more years than I can recall. I now live here permanently. I have travelled in 32 countries on 3 continents (Europe, Asia, Africa) so I am a bit of a traveller.
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