Creature record / 1897

The Avalanche Sea Serpents of Hạ Long Bay

July 1897 · Hạ Long Bay and the Baie de Fai-Tsi-Long (Bái Tử Long Bay), Tonkin, Vietnam

26Thinly documented Cryptid Creature 17 sources

July 1897. Hạ Long Bay, Tonkin. Two long, dark animals surface alongside the French gunboat Avalanche. Each is about 20 metres long. Their heads are small. They swim with a strange vertical undulation. Lieutenant Lagrésille orders a revolver cannon readied. The shot falls slightly short. Both animals dive, blowing noisily. He would see them again. Twice more in February 1898, among the islands of Fai-Tsi-Long, his crew chased the creatures and fired on them. Shells struck home. No wound showed. The last time, officers of the battleship Bayard stood on deck beside him. Two of them carried cameras. Nobody got a picture.

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Key facts

When	July 1897 to 1898
Time of day	not recorded
Where	Hạ Long Bay and the Baie de Fai-Tsi-Long (Bái Tử Long Bay), Tonkin,Vietnam
Duration	brief in July 1897; chases of about 1½ hours and about 35 minutes in February 1898
Witnesses	11
Witness roles	military
Found	testimony only
Evidence	none confirmed
Investigations	none recorded
Status	undisputed

The creature

Two dark grey animals about 20 m long and 2 to 3 m thick, with small heads, swimming on the surface with vertical undulations and blowing noisily as they dived. Later put at about 30 m, with smooth grey skin, black fins, a seal-like head twice as large, saw-tooth shapes along the back, jets of water vapour and three humps.

Size	about 20 m (reported length of each animal, July 1897)
Distance	about 600 m from the witnesses
Colour	grey, black
Sound	other sound

The Hexham Wolf of Allendale, Northumberland, 1904 (related)

Context

In the 1890s Tonkin was a French colony, and French gunboats worked the maze of islands in Hạ Long Bay. The bay's name recalls an old legend of a descending dragon. Popular retellings still link what happened next to that story.

Sources (17, most influential first)

Cryptid Profile: The Avalanche Sea Serpent Encounter · Pine Barrens Institute· 2018-08-28 · Wiki, blog, podcast · blog
Le Grand Serpent de mer observé de nouveau dans la baie d'Along · Comptes rendus de l'Académie des sciences (via BioStor/archive.org)· 1904 · Academic / paper of record · academic
Le Grand Serpent de Mer · Mythea· 2016-08-24 · Wiki, blog, podcast · blog
Exposé sur le légendaire serpent de mer · Inmysteriam · Wiki, blog, podcast · blog
Fringe Zoology: The Inconvenience of Disappearing Evidence · Skeptical Inquirer· 2024-12 · Press, book, documentary · news

Reputability

26/100Thinly documented

Keywords

People

LagrésilleLieutenant de vaisseau commanding the gunboat Avalanche; principal witness and author of the report
JoannetCommander of the battleship Bayard; witness to the 26 February 1898 encounter with nine of his officers
de La BédollièreAdmiral who informed the Governor-General of the sightings
Paul DoumerGovernor-General of Indochina, informed of the encounters
RacovițăAuthor of the 1903 paper in the Bulletin de la Société zoologique de France analysing Lagrésille's observations
Léon VaillantReported the 1904 Décidée sighting to the Académie des Sciences
Alfred GiardSuggested in 1904 that the Along Bay animal might be a surviving Tertiary reptile
Bernard HeuvelmansCryptozoologist said to have classed the case as a many-finned sea serpent

Names

Bernard Heuvelmans Heuvelmans A. C. Oudemans Académie des Sciences