Better than nothing

But Li Xiaochong, a volunteer with the Chengdu Bird Watching Society, told the Global Times that Ruo'ergai has set a generally good example for protecting wildlife in the country.

"Compared to many other highways in the country that have no warning signs of any kind, Ruo'ergai has done a good job," he said.

In Ruo'ergai no one knows how many animals are using the tunnels and how many are learning to adapt.

On an early Friday around 6 am the roadkill volunteers were driving back to Chengdu. Inside their van it was quiet and warm and most were sleeping, until the driver suddenly braked.

Jolted awake they saw about 40 yaks - adults and calves - calmly crossing the highway in front of them. Some spotted the van and stopped while others moved back to make way and some calves cautiously followed their mothers across.

"They seem to have been told by their mothers that they should look both ways before crossing the street," van driver Cai joked.

Everyone laughed. The van moved on and the herd moved on unscathed, at least for the moment.