Giraffe head
Twitter users tweeted photos of the two giraffes travelling along the Johannesburg motorway, moments before the fatal impact. Tony Hisgett

A blindfolded giraffe died after hitting its head on a bridge while being transported in an open truck on a motorway in Johannesburg, South Africa.

After the giraffe hit the bridge, the vehicle broke down and did not move for several hours, during which time the animal died.

The National Society for the Prevention of Cruelty to Animals (NSPCA) opened an investigation on the incident, which occurred on Wednesday.

"Two giraffes were being transported by road... one of the giraffes had an incident. We are not quite sure what happened, but we got unconfirmed reports that it hit its head on a bridge," Rick Allan, the NSPCA wildlife unit manager, told AFP.

The second giraffe is alive and well he said, and added that the investigation could possibly lead to "criminal charges against those responsible" as animals should be "transported in enclosed vehicles.

"There are lots of projectiles flying around on the highway [and] especially leaving an animal with its head sticking out blindfolded, is looking for problems."

According to The Times Africa, the giraffes were being transported to a game farm.

Shortly before the fatal incident, some people tweeted pictures of the two giraffes. One said, "Look how low that bridge is and how tall the giraffes are. Who thought this one through? I wish I hadn't seen this."

Dozens took to social media to express anger over the death of the animal, with some urging the investigators to press charges against the driver.