YELLOWKNIFE - Wildlife officials are investigating an online posting of a YouTube video showing three snowmobilers chasing down a herd of caribou.

This still picture was taken from a video posted on Youtube.com, showing snowmobile riders chasing a herd of caribou across a lake. Such activity is illegal, according to a wildlife official. - still capture from YouTube.com

The two-minute, 22-second video opens with a scene of a frozen lake flying by as the group closes in on a small herd of caribou. The video, entitled "Racing with caribou," is equipped with sound. Viewers can hear the snowmobile engines whine as the snowmobilers give chase.

The video was filmed by one of the snowmobile riders.

The caribou are in full gallop as the snowmobilers approach, and continue to run at top speed as the snowmobilers race beside them for the duration of the video.

The video shows one snowmobiler racing on the opposite side of the herd as both caribou and their pursuers continue down the lake.

Another snowmobiler is seen coming up behind the one holding the camera as the trio stops their chase and the video ends.

Section 38 (1) of the NWT Wildlife Act states: "No person shall... persistently or repeatedly chase, weary, harass or molest wildlife without intending to capture or kill it."

The YouTube website dates the posting of the video as Jan. 18, 2007. The poster's name is Andre Thibodeau, who works as the network administrator at City Hall.

The web page includes several comments from viewers. One viewer states, "wicked video Andre."

Another viewer chastises Thibodeau: "Leave the caribou alone you moron," to which a post bearing his name replies, "Well at least I don't buzz them with wings... I heard the rumors about you."

When reached for comment Friday, Thibodeau said he was unaware that it is illegal to chase caribou, but insisted that he didn't shoot the video or was even present.

He said "an acquaintance" gave it to him, after which he posted the video on YouTube.

"I wasn't even there, I just posted the video," said Thibodeau.

"I know one guy fairly well. The other two I really don't know them at all. One of the guys I don't even know what his name is. I have no idea."

He said he didn't know on which lake the video was shot either. He refused to identify the snowmobilers in the video. He said he posted the clip because he thought "it was a good video."

A few minutes after the interview with Thibodeau concluded, the video was removed from YouTube.

Raymond Bourget, senior wildlife officer with Environment and Natural Resources, said chasing caribou for sport is "absolutely illegal."

"It affects their ability to survive," said Bourget.

"They're expending valuable energy they need simply running. It also leads to exhaustion. It can lead to respiratory illness, pneumonia from heavy breathing in cold air for extended periods of time.

"It can result in injury if they stumble or something. The increased stress - they're more on edge and don't feed so much."

The maximum penalty under the Wildlife Act is a $1,000 fine, a year in jail, or both.

Caribou have dominated the news in recent years as government surveys indicate caribou herds across the territory are in sharp decline.

Bourget said his department became aware of the video some time ago, although he wouldn't say when.

He said a copy of the video was recorded and the department is conducting an investigation.