Thirty live pangolins have been found individually wrapped in a box on a bus in Vietnam’s Ha Tinh province that had come from Laos.
The small, docile pangolin’s scales are used in traditional medicines to treat allergies and impotence.
Pangolins curl into a ball when scared, making them easy targets for hunters.
Save Vietnam’s Wildlife said four of the pangolins were dead and others were in poor health.
The NGO’s Truong Van Truong said: “Most were dehydrated and weak because they were kept in a tight space for a long time.”
They were tied into individual sacks and crammed into the box, where they might have been kept for weeks with limited water or food, he said.
The Vietnamese police said the driver and his wife were arrested on suspicion of taking money to transport the endangered animals.
The pangolin is found across Asia and Africa, with one snatched from the wild every five minutes, according to the World Wildlife Fund. They once roamed Vietnamese forests, but their numbers have plummeted with poaching and habitat loss.
Pangolins were now “critically endangered”, the International Union for Conservation of Nature said.
The scaly anteaters would be nursed back to health and the strongest released back into the wild, Truong said.
Vietnam is both a consumption and transport hub for illegal wildlife trafficking in Asia.
Police arrested a trafficking suspect and two others after finding seven frozen tiger cubs in their car in a Hanoi car park last Thursday.
It is believed they had been smuggled in from Laos. It was unclear whether the tigers had been killed in captivity or shot in the wild. Tiger meat is prized in Vietnam and its parts are used to make jewellery and medicine.
The same day 125kg of rhino horn encased in thick plaster was seized at Hanoi’s Noi Bai airport.
The horns were smuggled from the United Arab Emirates on an Etihad flight. It took over half a day for customs officers to break all the 55 packages open.
The horns, when ground to a powder, are believed in Vietnam to have medicinal qualities to cure cancers, hangover and other ailments. It can cost up to US$60,000 per kg with last week’s haul valued at US$7.5 million.
The docile pangolin. Picture credit: Wikimedia