Khon Rak Ling Huajai Kraeng Club president Kawinpat Mongkholtecha-phat said yesterday that officials would check the lump further to determine if it was malignant.

The 10-year-old long-tailed macaque, nicknamed “Lung Ou-an” (Uncle Fatty), would be given antibiotics for another week, he said. If its condition improved and there were no complications, it would be released.

Lung Ou-an weighs 15 kilograms, much bigger than the average macaque of between 8 to 10 kilograms.

Officials from the Department of National Parks, Wildlife and Plant Conservation captured it near a floating market by using a sedative shot on Thursday. It was then taken to a wildlife rescue centre in Nakhon Nayok for a health check including chest and abdomen X-rays.

Lung Ou-an’s physical condition was initially believed to stem from obesity as people would feed the local long-tailed macaques. It led a 100-strong herd among the 300 long-tailed macaques that roam the Bang Khunthien attraction.

Every day, it would lead fellow macaques to collect donated food before the herd would swim back to the other side of the river where they resided. Many of Lung Ou-an’s herd members also show signs of being overweight.

Kawinpat said it was very difficult to control the food intake of the long-tailed macaques.

“We can’t just place signs preventing people from feeding them here because they don’t have any other food source but from people. The club would like to ask people to reduce the food amount to feed them so it would be just enough to prevent them from starving rather than overfeeding them,” he said.

The local club also planned to launch a project to sterilise the Bang Khunthien long-tailed macaques later this year.

He said they were currently raising funds to meet the target Bt200,000 for the project.