The great white shark's mastery of the open ocean has been revealed by scientists who have followed one of the fearsome fish from South Africa to Australia, and back again.
A young female dubbed Nicole was tracked by satellite on an epic 11,000-kilometre swim from the shores of South Africa's Western Cape province across the Indian Ocean to Exmouth Gulf, Western Australia, in 99 days.
Just six months later she was photographed at the cape again.
It was claimed as the fastest trans-oceanic round trip recorded by any marine animal in a report to the US magazine Science
by a New York researcher, Ramon Bonfil, of the Wildlife Conservation Society, and South African colleagues. The finding raises the prospect that South African and Australian great white shark populations are physically connected, and that the endangered, totally protected species may be vulnerable to high-seas fishing.
The 3.8-metre female, named by Dr Bonfil after the Australian actor and great white supporter Nicole Kidman, swam through seas that are heavily long-lined for tuna and shark.
Her journey also underlines the difficulty of re-sighting a great white that may have attacked a person. Since July 2004, the species has killed four people in Australian waters, and another two have escaped with serious injuries.
Great whites were long believed to live mainly in waters over continental shelves, and some of the fish tagged by the South African group stayed nearby or travelled up the southern African coast. But Nicole's odyssey raises the prospect that the sharks routinely make intercontinental trips too.
In hair-raising work, the scientists in South Africa used baited lines to wrangle great whites into a steel cradle slung from the side of their research vessel off the Western Cape. Dr Bonfil and others then climbed over the sharks to fit tags into their dorsal fins before they were released.
Nicole was first identified in 1999 from a distinctively notched dorsal fin. She had been sighted 38 times at Gansbaai, near Cape Town since then.
On 7 November, 2003, she was darted with the 17-centimetre pop-up tag while free-swimming. After initially heading out into the South Atlantic, she turned into the Indian Ocean and swam east to Australia.
Swimming most of the time near the surface, the shark might have been using cues from the sun, moon or stars as a navigational aid, or have been following gradients in the Earth's magnetic field.
Nicole swam to within two kilometres of the Australian coast, just south of Exmouth Gulf, arriving during the mating season for great whites in the region.
The tag automatically released on 28 February, 2004, and fed data on the journey by satellite to the researchers. Nicole was photographed again on 20 August, 2004, off Gansbaai, having completed a 20,000-kilometre round trip.