GETTY / ALHPA The Baiji dolphin may have come back from the dead following claims it has been spotted

A researcher sighted a grey-white creature with a long snout leaping from the water along a stretch of China's greatest river. There were no photos taken of the animal as it jumped at least three times at a distance of up to 300 yards from a research boat that had set out to look for one the most elusive creatures on Earth. The Baiji, or Yangtze river dolphin, was declared functionally extinct a decade ago because there were too few individuals left to sustain the species.

Yet hopes have lingered that the eight-foot long, almost blind cetacean lingers upstream around small sandbanks and backwaters of the 4,000-mile river. Expeditions have continued to be mounted in recent years with the remote hope of finding a relict population, although the last significant count was in 1998 when seven were recorded. Since 2004 there have been no confirmed sightings but China's Academy of Sciences have dispatched experts to look into Tuesday's sighting near Wuhu in Anhui province.

ALPHA A researcher sighted a grey-white creature leaping from the water along China’s greatest river

According to local television, a nongovernmental expedition of 20 animal protection volunteers has been searching the Yangtze in recent weeks in four fishing boats along a 500-mile stretch of river. On Tuesday, the team spotted an aquatic animal with a distinctive long snout leaping from the water. They immediately put sonar detectors into the river to locate the creature but did have time to get a photograph. News of potential Lazarus moment for a creature driven to the brink because of Maoist dogma was greeted with cautioned optimism by leading conservation groups.

This possible sighting of a Baiji river dolphin is very encouraging news Danny Groves of Whale and Dolphin Conservation

Danny Groves of Whale and Dolphin Conservation said: "It isn't impossible that this was a sighting of a Chinese river dolphin and it would be wonderful news if dolphins were found to be surviving in the river. "It would not be the first time something previously thought to be extinct is rediscovered; earlier this week an 'extinct' species of tree was found growing in the Queen's garden. "However, the Yangtze River, the only home of the Chinese river dolphin, remains heavily polluted and degraded."

GETTY Expeditions have continued to be mounted with the remote hope of finding a relict population

The International Fund for Animal Welfare, a major global player for whale and dolphin protection, is also cautiously optimistic. "This possible sighting of a Baiji river dolphin is very encouraging news, as these dolphins are among the most endangered in the world," said Sharon Livermore, IFAW Whales Programme Officer "The severe pollution issues and poor health of the Yangtze river have had devastating impacts on this dolphin population and complete extinction of this species would be a tragedy for conservation."

The ancestors of the Baiji first arrived in the Yangtze river system from the Pacific Ocean 20 million years ago and slowly evolved to a life in fresh water. As a species, it was never numerous with as few as 5,000 individuals when they were described in the ancient Erya dictionary 300 years BC. Over the centuries, a legend grew up around the mythical creature about the young princess Baiji who was thrown into the Yangtze by her furious father because she refused to marry a wealthy man she did not love. The river gods took pity, turning her into a dolphin so she could swim the waters for eternity.

GETTY The Baiji, or Yangtze river dolphin, was declared functionally extinct a decade ago