Thanit Nooyim, director of the 12th Conservation Area Management Office of the National Park, Wildlife and Plant Conservation Department, led a team of veterinarians to perform the sterilisation of the captured monkeys.
He said the measure was needed as long-tailed macaque populations were growing in several areas of Nakhon Sawan, causing increasing nuisance to local residents.
The sterilised monkeys will be released into the wild after their surgery scars have healed.