A rare roving walrus arrived in Iceland in February after a four-month tour of the waters of western Europe. The marine mammal, nicknamed Thor, captured the attention of crowds as he stopped to rest on beaches and in harbors along his journey. 

First spotted in the Netherlands and France in November 2022, Thor then headed up to Hampshire in southern England. He rang in the New Year in Scarborough, England, where locals canceled their fireworks so as not to disturb him. Most recently, he was spotted in Breiðdalsvík on Iceland’s east coast.

“After Thor’s visit to the U.K., we wondered if we would ever see him again,” a spokesperson for British Divers Marine Life Rescue (BDMLR) said, per BBC News. “We are delighted to have been informed that he is in Iceland.”

Walrus sightings in Europe are rare. In the past 130 years, only about 27 have been reported in U.K. waters, London’s Natural History Museum (NHM) wrote in 2021. But some experts warn that as the ocean warms because of climate change, arctic animals may increasingly be forced from their homes. Loss of their sea ice habitat is already leading walruses increasingly rest on land and travel as far as 100 miles to look for food, per the museum.

Walruses are listed as vulnerable on the International Union for Conservation of Nature’s Red List of Threatened Species, though the last assessment was in 2016. At that time, it was estimated around 112,500 mature individuals existed on the planet. 

“The lives of walruses, like those of polar bears and seals, are changing,” biologist and natural historian David Attenborough said in a documentary, per the Observer’s Robin McKie. “All are living at the frontier of climate change, and all are suffering as a result.” 

Thor may have traveled to Europe all the way from the Canadian Arctic, per BBC News. He’s thought to only be between three and five years old—relatively young for these pinnipeds, which can live to around 40. He also likely weighs roughly 1,650 pounds, Dan Jarvis, the director of welfare and conservation at BDMLR, tells the National’s Xander Elliards. Males can grow up to more than twice that size—4,000 pounds and 12 feet long.   

While walruses mostly live in and around the Arctic Circle, fossil remains suggest they were once more widespread, per NHM. Thor is likely an Atlantic walrus, which dwell mainly in the northern waters of Canada, Greenland, Norway and Russia, said Rod Downie, the World Wildlife Fund’s chief polar adviser, to BBC News in December.

Thor’s European tour is uncommon, but it’s not unprecedented. In recent years, walrus sightings appear to be increasing in Europe. Last year, a walrus named Freya was sighted in U.K., Dutch, Danish and Swedish waters before being euthanized in Norway when officials declared her a threat to human safety. The year before, Wally the walrus traveled to several countries, including Wales, France and Iceland. After capsizing and sinking several boats in Ireland by climbing aboard, officials built him his own pontoon to rest on. And last week, a fisher spotted another walrus on the western coast of Scotland.

Downie told BBC News that it would be “difficult” to attribute these sightings directly to warming trends. “Walruses like colder waters, so it would be counter-intuitive to see more of them here—as arctic waters warm, they would instinctively go further north to colder waters,” he told the publication. Still, “walruses are living on the front line of climate change and face massive threats as sea ice diminishes.”

But due to the unusual nature of these walrus sightings, Molly Gray, the rescue and community organizer of the BDMLR, tells the Guardian’s Mabel Banfield-Nwachi that climate change might be at fault. “It could be a bit of a pattern,” she tells the publication. “We could definitely see more, but who knows.”

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