Mythical creatures: sea serpents

Explore the stories behind the Fantastic Beasts™: The Wonder of Nature exhibition. How fantastic marine life inspired terrifying mythical sea monsters.

The Natural History Museum

LIFE Photo Collection

Sea monsters

In the past, sightings of oarfishes, giant squids and other unfamiliar animals led sailors to tell tales of terrifying sea monsters such as the kraken.

Sea serpent by Olivia Lomenech Gill (born 1974)The Natural History Museum

'Sea serpents are found in the Atlantic, Pacific and Mediterranean seas. Though alarming in appearance, sea serpents are not known ever to have killed any human, despite hysterical Muggle accounts of their ferocious behaviour. Reaching lengths of up to a hundred feet, the sea serpent has a horse-like head and a long snake-like body that rises in humps out of the sea.'
– Newt Scamander, Fantastic Beasts and Where to Find Them™

Fantastic Beasts and Where to Find Them™ describes many magical creatures that live in the sea. The Hippocampus, a beast also found in ancient Greek mythology, is half horse and half giant fish. The spiny Shrake rips up fishing nets. The Ramora is a gigantic magical fish that anchors ships and protects seafarers.

Artist Olivia Lomenech Gill looked to the natural world for inspiration while creating artworks for an illustrated edition of Fantastic Beasts and Where to Find Them™. Lomenech Gill writes that her etching of the sea serpent 'was completely inspired by the oarfish, which I never knew about until working on this book. How fantastical that such creatures actually exist!'

Giant oarfishThe Natural History Museum

Bones of a monstrous fish

Giant oarfishes can grow up to eight metres (26 feet) long, making them one of the longest fish in the sea.

Giant oarfishThe Natural History Museum

Scientists know little about the behaviour of giant oarfish. This is because they live in the deep ocean and our interactions with them at the surface are often during periods when they are under stress, meaning that their behaviour at that time may not be usual.

However, rare glimpses of their silvery, snake-like bodies and bright red fins are thought to be behind many tales of sea serpents.

Newspaper cuttingThe Natural History Museum

Richard Owen, sea-serpent killer

Reports of sea serpent sightings fill this scrapbook from the 1800s. It was made by scientist Richard Owen, who was sceptical because no physical evidence of these monsters had ever been found.

He suspected that sailors were simply misidentifying seals, whales and other marine creatures, a view that earned Owen the nickname Sea-Serpent Killer.

LIFE Photo Collection

The kraken

Tales of the mythical kraken describe a gigantic octopus-like creature that attacked sailors and even entire ships.

Today it is thought that sightings of giant squids and other large cephalopods such as octopuses may have inspired these stories.

Giant squidThe Natural History Museum

Origins of the kraken

Encounters with giant squid are thought to be the most likely explanation for tales of sea monsters such as the kraken.

These deep-sea animals are rarely seen alive, but dying squid are sometimes spotted near the water's surface or washed up on beaches.

Much of what we know about them comes from studying remains such as these, which were found in the stomach of a sperm whale.

Giant squid modelThe Natural History Museum

'Sitting near the lake, watching the giant squid waving its tentacles lazily above the water, Harry lost the thread of the conversation as he looked across to the opposite bank.'
– Harry Potter and the Prisoner of Azkaban™ (book)

Like most species of squid, these deep-sea giants have eight arms, a parrot like-beak and two long tentacles covered in sharp, toothed suckers used to catch prey.

Researchers estimate that giant squids can grow up to 13 metres (43 feet) long.

Giant squidThe Natural History Museum

In 2004 the Museum was offered a nearly complete specimen of a giant squid. It had been accidentally caught at a depth of 220 metres (700 feet), by a fishing trawler.

Giant squidThe Natural History Museum


At 8.62 metres long, the specimen was a challenge to preserve and house, but it was too good an opportunity to miss.

Giant squidThe Natural History Museum


When it had been caught it was immediately frozen. This meant that DNA samples could be taken before decay set in. In 2013 these DNA samples helped to prove that there is just one species of giant squid, Architeuthis dux.

Giant squid Architeuthis dux (2004)The Natural History Museum

Rostrum of two spearfish (Marlin) embedded in ship timberThe Natural History Museum

A ship under attack

There is no proof that a sea monster has ever attacked a ship, but it seems like some fish have given it a try. This plank of wood from HMS Farquharson still contains 'the horns of some fish' that pierced the ship in 1832.

Rostrum of two spearfish (Marlin) embedded in ship timberThe Natural History Museum

Scientists from the Natural History Museum in London helped to identify these 'horns' as the sharp rostrums (snouts) of two marlin.

Marlin Fishing (1946-08) by Sam ShereLIFE Photo Collection

Marlin are among the fastest fish in the sea, swimming at speeds of up to 130 kilometres (80 miles) per hour. Recent studies suggest they use their sharp rostrums to stun or kill prey.

Credits: Story

For more information and to book tickets to the exhibition, visit the Museum's website.

To find out more about the Wizarding World, visit WizardingWorld.com

WIZARDING WORLD and all related trademarks, characters, names, and indicia are © & ™ Warner Bros. Entertainment Inc. Publishing Rights © JKR. (s21)

Credits: All media
The story featured may in some cases have been created by an independent third party and may not always represent the views of the institutions, listed below, who have supplied the content.
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