Fabled Irish ‘sea monster’ — dating to medieval times — may have a simple explanation
Like Loch Ness in Scotland, the Shannon Estuary in Ireland has long been home to a fabled sea monster.
Known as a Cathaigh — or Cata for short — the mysterious creature is rumored to lurk in the brackish waters where the River Shannon flows southwest into the Atlantic Ocean.
Over the centuries, the fantastical beast has reportedly been sighted on several occasions — beguiling locals.
But now, a new visitor might offer a simple explanation.
In late November, a humpback whale was seen swimming in the estuary for the first time, surprising experts.
“There have been reports of species larger than the resident bottlenose dolphins in the inner estuary, but never has evidence such as a photograph or video been obtained,” the Irish Whale and Dolphin Group (IWDG), a cetacean conservation charity, said at the time. “To be honest, none of us would have believed this sighting without the evidence.”
The whale, which has remained in the area for weeks, could help demystify the phenomenon of the Cata. This is because similarities between the Cata and humpback whales “are striking,” the IWDG said in a Jan. 7 post on Facebook.
In 1922, the Cata was described as having “a massive black, cone-shaped hump, which rose a few feet out of the water.” Further, it was said to make “a blowing sound, like a porpoise makes when it surfaces for air.”
These descriptions were retold by Shane Mac Olon in his 1991 book “Cata: The Monster of Shannon Waves.”
“Was this sighting reported in 1922 of a humpback whale in the Shannon?” the IWDG said.
After noting the similarities, the group proposed naming the newfound humpback Cathaigh — in honor of the mythical creature.
More about the Cathaigh
A 15th century manuscript describes the Cathaigh as the protector of Scattery Island, located in the Shannon Estuary, according to research from the University of Limerick.
It supposedly had the mane of a horse, the tail of a whale, two feet and “a fiery breath ... which burned like embers.”
The supernaturally ordained creature was said to be “ruthless” and “awful,” killing anyone who set foot on the island.
But at some point, St. Senán, born in the fifth century A.D., is believed to have exiled the Cathaigh from the island before establishing a monastery there, according to the University of Limerick.
Despite being banished, the legendary creature has reportedly been sighted in the estuary during more recent times, including in 1871, 1922 and 1976.
Similar to in 1922, the creature was described by an alleged witness in 1976 as having “the size and shape of a large submarine, with a twelve foot long neck and massive cone shaped hump.”
McClatchy News reached out to the IWDG for comment and was awaiting a response.
This story was originally published January 10, 2025 at 1:16 PM with the headline "Fabled Irish ‘sea monster’ — dating to medieval times — may have a simple explanation."