A coyote recently stunned observers by swimming to Alcatraz, braving the treacherous waters surrounding the notorious former prison island off the coast of San Francisco in plain view of a tourist recording video.

The coyote in question is thought to be the first ever to reach Alcatraz, now a tourist attraction, in that manner. While it’s uncertain why the animal doggy-paddled there, the consensus is that the creature probably came from San Francisco – about 1.25 miles away – or other islands near Alcatraz where coyotes have been spotted.

Aidan Moore of Alcatraz City Cruises published clips of the coyote video on his Facebook account on 11 January. “A coyote swim to Alcatraz from the main island!” wrote Moore, who later told the news outlet SFGate that he got the videos from a tourist who approached him while at work. “The most exciting thing to happen here in ages! That’s a mile and a quarter swim!”

The clips depict the coyote swimming all by its lonesome in the San Francisco Bay, bobbing its head as it determinedly headed toward Alcatraz. The coyote eventually emerged on to the island’s rocky shore, cutting a bedraggled figure as water dripped from the animal’s body, which seemingly shivered with the Golden Gate Bridge looming in the background, according to one of the videos.

Moore said to SFGate that he called in the sighting to rangers at Alcatraz, which is under the jurisdiction of the US national park service. But it had disappeared by the time the rangers went looking for the coyote, and the canine’s fate was unclear.

SFGate reported that a spokesperson for the Golden Gate national recreation area – which oversees Alcatraz – confirmed the authenticity of the coyote sighting. The spokesperson, however, could not elaborate on what motivated the coyote to go there.

Citing what it described as a self-taught naturalist who has been documenting local coyote behavior for two decades, San Francisco’s CBS affiliate reported on Tuesday that the animal may have been seeking out new territory amid interspecies population pressure.

“This one was probably pushed around by other territorial owners and decided that he could make this trip,” Janet Kessler told the outlet, adding that coyotes have been in and around San Francisco for generations. “So, he attempted it, and he made it.”

Both Kessler and Moore remarked on the coyote’s evidently worn state. “He didn’t look like he was in very good condition, which I’m not surprised by given the harrowing experience,” Moore told SFGate.

Kessler, meanwhile, said to CBS: “He can barely make it. He’s depleted. He is shivering. He is cold.”

It wasn’t immediately clear what happened to the coyote after it was recorded getting to Alcatraz. Nonetheless, Kessler noted to CBS that the coyote had resources on the island with which to survive, including banana slugs, mice, rats, birds and puddles of rainwater.

“They are survivalists,” Kessler said to the outlet of coyotes in general. “That’s why they continue to expand.”

The federal government shut down its maximum-security prison on Alcatraz in 1963 after nearly 30 years in operation.

Some of its most infamous prisoners included the mob boss Al Capone, bootlegger George “Machine Gun” Kelly and Boston gangster James “Whitey” Bulger. The frigid, rough waters surrounding Alcatraz lent to it a reputation of being virtually inescapable.

The prison was later reopened as a public museum that attracts more than 1 million visitors annually.