An eight-year-old tortoise and a three-year-old dog have become online hits after a video of them playing chase went viral online.

In the video, the African spurred tortoise, called Sheldon, is seen moving at remarkable speed as it chases his friend Dolly, an American pit bull terrier, around its owner's garden.

The dog barks playfully as the tortoise follows it across the grass.

The footage was posted online in February by animal rescue and veterinary body the Humane Society of North Texas. It was filmed in August 2014 by one of their vets, Dr Cynthia Jones, who adopted the two animals.

She said Sheldon only plays chase with Dolly and not her other pet which is a Labrador retriever.

HSNT representative Whitney Hanson said she hoped the video helps to open people's eyes to the possibility of interspecies friendships.