The video shows a black bear rummaging around a rubbish bin in the Canadian woods, where an American bowhunter was waiting, armed with a spear - custom-made and outfitted with a camera to capture the kill.
Josh Bowmar pulled back the spear and let it fly - nearly 12m, into his prey.
"I just did something that I don't think anybody in the world has ever done," he said on camera, according to the Edmonton Journal.
He added: "He's going down; I drilled him perfect. That was the longest throw I ever thought I could ever make."
After impaling the bear, Bowmar is seen on his knees, holding his head and smiling and laughing.
The video is believed to have been filmed in May during a hunting trip in an area not far from Edmonton, Alberta. It was eventually posted online by Bowmar, who later set it to private.
But the footage was recently republished by the Daily Mirror and Wildlife Planet, among others, and went viral, drawing outrage from critics - in part because Bowmar let the bear die on its own, leaving the area after he speared it, according to the Edmonton Journal.
Bowmar told the Canadian Broadcasting Corporation that his team left because it was dark and raining; they went back the next morning to retrieve the bear, which had staggered some 50m before it collapsed and died.
The bear "died immediately," Bowmar told the Canadian Broadcasting Corp., and the kill was "as humane and ethical as one could get in a hunting situation on big game animals".
But critics disagreed, calling the act "barbaric" and "unnecessary". They have called Bowmar and his wife, Sarah, who is also a hunter, "psychos" and "worthless garbage," with one adding: "I hope you die a slow painful death".
"This bear did not die a quick and painless death," Help Save the BC Black Bears wrote. "It ran off after being mortally wounded and Josh decided to wait until the NEXT DAY to track his 'prey.' Disgusting."
Bowmar did not respond to requests for comment, but the 26-year-old Ohioan said in an email to the Canadian Press that people have been hunting with spears since the "dawn of man".
Bowmar was an all-American javelin thrower at Heidelberg University, a Division III liberal arts college in Tiffin, Ohio.
"A javelin is pretty much a giant spear," he said during a recently Q&A on his YouTube channel. "I was really good at throwing this javelin, so I naturally transitioned into spear-throwing."
His video-sharing channel is filled with footage showing him on bowhunting adventures with his wife, Sarah.
"I enjoy the challenge of the hunt more than the actual harvest," Bowmar said in the Q&A. "So for me, it's not about going out there and shooting everything I see. . . . I really like the pursuit, I really like finding an animal and studying that animal and getting as close as possible to be able to kill him. I'm not against gun hunters by any means but, for me, I get so much more from bowhunting than I did from gun hunting."
In the Q&A, filmed in a vehicle around the time the bear-spearing footage went live, Bowmar was asked: "How savage are you?"
"Well," he replied, "I did kill a bear with a spear on the ground. I guess that makes me pretty savage, right?"
His wife quipped, "You're pretty savage. I would say you're like a 9.5 on a scale of 10."
He responded: "If I would have killed it with my bare hands, I think I would have been pure savage."
The spear is thought to date back 20,000 to 25,000 years, according to a 2006 article in National Geographic. It was relied on heavily by Native Americans, who used spears for hunting and during war, according to the American Indian Heritage Foundation.
"As long ago as 10,000 years ago, archaeologists believe that the earliest Native Americans inhabitants, known as Paleo-Indians, used very primitively made spears to hunt animals such as mammoths, mastodons, bison, and smaller animals," the foundation states.
"They would chip away a large rock to make a spearpoint as sharp as a razor. Soon, they developed a new tool called an atlatl. This tool helped them launch spears very quickly and with great force, so they could kill the animals while still at a safe distance."
Bowmar told the Edmonton Journal that he never wastes the animals he hunts and kills.
"In fact, it is even against the law to waste the animal's hide," he said in a statement to the newspaper. "We also eat the meat from our harvested animals including bear. On top of tasting amazing, it's extremely nutritious for our bodies."
In Alberta, bear baiting - using food scraps to attract the animals, then hunting and killing them - is legal in some areas. So is spear hunting.
Hunting should be done with the most effective means possible to ensure you have a quick and immediate death as possible
But after Bowmar's video went viral, Alberta's Ministry of Environment and Parks said it was in the process of revising its hunting regulations.
"The type of archaic hunting seen in the recently posted video of a hunter spearing a black bear, allegedly in Alberta, is unacceptable," the ministry said to the Washington Post, adding: "We will introduce a ban on spear hunting this fall as part of those updated regulations.
"In the meantime, we have asked Fish and Wildlife officers to investigate this incident to determine if charges are warranted under existing laws."
Alberta Fish and Game Association President Wayne Lowry told the Edmonton Journal that because spear hunting is so uncommon, "it's never really had to be dealt with in the legislation, but knowing that it is being done in other countries and other jurisdictions, we figured it would show up here sooner or later."
He said weapons such as bows or firearms can lead to a speedier death to ensure the animals do not suffer needlessly.
"Hunting should be done with the most effective means possible to ensure you have a quick and immediate death as possible," he told the newspaper.