The first sighting appears to be in 1903 when one reportedly attacked three people. It was described as a huge buffalo-like creature that roared retreated underwater when they shot at it .
In August 1962, there were over reported sightings of two creatures chasing one another through the water.
In 1968 a Jilin Province Weather Report Department staff member, Chou Fon Yin, was visiting the lake when he saw a wave emerged from the north eastern side and then two black points rose out of the water. Chou using binoculars to get a closer look said that the two black spots were two large creatures swimming side by side. He described them as black and grey in colour with very dog like heads. Their movement in the water left a wake 21 feet( 7 metres) long.
In July 24, 1994 a group of more than 40 tourists, including a Japanese university professor (no name given ), all claimed to have watched, and photographed, the Monster as appeared on the lakes surface for almost 30 minutes. Also in 1994 a Chinese State Media report quoted a sightseer by the name of Meng Fanying who stated that he watched the creature leap from the water, in a seal like fashion, 30 feet off shore.
In July 2005, the China Daily published a report about a 52 year old man ,Zheng Changchun, who with his daughter and his son in law saw and video taped the creature Zheng was quoted as saying they saw a strange, black object emerging from the water and he grabbed his video recorder.
In September 2007, Chinese news reporter Zhuo Yongsheng shot a 20-minute video of several creatures swimming in three pairs. He said they were seal-like, finned creatures that spent around an hour and a half, swimming in the lake. "They could swim as fast as yachts and at times they would disappear under the water. It was impressive to see them all swimming at exactly the same pace, as if someone was giving orders," he said. "Their fins - or maybe wings - were longer than their bodies."
The Reuters report from 1994:
With sightings of a blond-headed creature -- or perhaps a "black thing as big as a bull head" -- to go on, officials at Lake Tianchi (Heavenly lake) in northeast China's Jilin province have started establishing study societies and collecting videotapes and photographs of a strange swimming object, Xinhua news agency said on Friday. The official news agency said eyewitnesses had seen a creature moving as fast as a walking man twice in the past two weeks. "At 3:25 p.m., September 2, it was clear and the swimming creature surfaced its blond head and swam from north to southwest in the lake for ten minutes before it submerged, according to Kim Taik, deputy secretary-general of the Yanbian Korean Autonomous Prefectural People's Political Consultative Conference," the news agency said. Kim said the creature stirred up waves two metres (six feet) high. Xinhua quoted a travel guide who was taking a group of Korean tourists to the lake as saying she saw a large black "thing" swimming in the lake. It said local people have given accounts of sightings and taken pictures of a mysterious lake-dwelling creature since the beginning of the century. The creature is not
(c) Reuters Limited 1994 REUTERS NEWS SERVICE
It may be my reading of the reports but it sounds like some sort of seal. The roaring one from 1903 could have been a bull seal as they have a mane and it would look like buffalo. The fins are interesting as I believe some whales have huge fins . So could it be two different types of creature, one a seal like animal , the other a whale like creature? The lake is deep enough from them both to live there but there is little information on whether the food stocks would be sufficient.