Dozens of crab-eating macaques stuffed in cages and destined for China allegedly for medical use have been rescued by authorities in Thailand.

Forty-seven of the protected wild animals were found crammed in plastic crates on the back of a pick-up truck driving through Nakhon Ratchasima province on Monday, March 6.

Police tightened security at checkpoints in the province after learning of the possible wildlife shipment passing through.

They intercepted two pickup trucks at the Samrit intersection of Mittraphap Road, Highway No. 2 at around 2 AM on Monday.

One of the trucks was found to be carrying dozens of crab-eating macaques suffering as they were stuffed in net bags inside plastic cages. One of the monkeys had fallen ill.

Natural Resources and Environmental Crime Suppression Division and national park officials jointly arrested Kitsana Srimoros, 37, and Kritsda Muensri, 43, both from Thailand.

Kritsana said that he was hired for 17,000 baht (492 USD) to transport the animals from Khao Takhrong National Park in Ratchaburi province to the Thai-Laos border in Nong Khai province. He claimed he did not know anything about his employer.

Both suspects were charged with illegally possessing and trading protected animals and were taken to the Non Sung distirtct Police Station.

They face a penalty of up to five years in jail, a fine of up to 500,000 baht (14,470 USD), or both.

The penalty for illegal wildlife trading is detention for up to 10 years, a fine of up to 1,000,000 baht (28,940 USD), or both.

Peersasak Paksasuay, director of natural resource conservation and protection for Protection Areas Regional Office 7 in Nakhon Ratchasima, said that the Natural Resources and Environmental Crime Suppression Division were coordinating with national park staff to prevent animal smuggling.

He said that the drivers were hired separately to transport the animals. They reportedly did not know each other and merely drove the animals from point to point before passing the keys over to other drivers.

It is believed the macaques, a protected animal under Thai law, were being sold to China to be made into traditional Chinese 'elixirs.'

Peerasak said that the rescued macaques will be taken to the Phu Khiao Wildlife Husbandry Research Station in Chaiyaphum.