Two thrill-seeking adventure divers have put a new spin on the phrase taking a tiger by the tail.
The daring duo filmed themselves swimming with tiger sharks as the animals devoured a whale carcass.
At one point, one of the divers grabs a shark's dorsal fin and is towed for a short distance.
In another, a shark brushes past and is stroked by a diver.
The film was shot near Australia's Great Barrier Reef - in the Coral Sea about 60km north of Port Douglas, Queensland.
Cairns travel agent Clint Carroll, who posted the footage on his travel blog site, told the Cairns Post the divers were members of the diving fraternity, but wanted to keep their identities a secret.
The film is understood to have been shot in January.
New Zealand shark expert Clinton Duffy says the tiger shark - which is common in tropical and sub-tropical waters around the world - has a fearsome reputation, and has been known to eat anything, from licence plates and coils of wire, to turtles, whales and "the odd surfer".
While the stunt might appear dangerous, the two divers were "probably pretty safe", as the sharks would be focused on devouring the whale, he said.
Tiger sharks are common in tropical areas, and in one case more than 200 of the creatures turned up to finish off a single blue whale carcass in New Caledonia.
They are also frequent visitors to New Zealand waters.
A school of tiger sharks was spotted feeding on a whale carcass near Great Barrier Island in January, and fishermen tagged and released a 300kg tiger shark in the same area last month.
The animals can grow up to 5m, though there are reliable reports of tiger sharks more than 6m long, Mr Duffy said.