A shocking video of a herd of whitetail deer jumping off a bridge to their death has surfaced on the internet. Catherine Veerhusen and her husband witnessed the harrowing sight while driving across a highway bridge in Linn County, Iowa, US on 10 December.

"This just happened. Horrifying," a shocked Catherine wrote while sharing the video and few images of the incident on Facebook. The video has since gone viral over the internet and has garnered over 27 million views.

The clip is roughly 3 seconds long, but the content left many viewers heartbroken. In the video, a lone buck first jumped to its death from the bridge, which is about 20 to 30 foot high, and three more followed suit.

"I've never seen anything like this. No words, no words," Veerhusen told Des Moines Register. Many viewers assumed it was a suicide, while others believed they may have mistaken the other side of the bridge as plain land.

"There's that suicidal deer crossing," one internet user commented on the post.

Ron Lane, a conservation officer with the Iowa Department of Natural Resources, ruled out suicide by the animals. He told the news outlet that the herd must have gotten disoriented or frightened due to the hunting season, and were also not familiar with the area.

"The bridge there is brand new. I'm guessing the deer aren't used to that, with all of the construction going on. It sounds like with they were just trying to run across and didn't know where to go," he noted.

Meanwhile, explaining the scene in the video, Veerhusen told the news outlet, "We see these deer cross the ramp in front of us and we're like, 'OK, don't go over the bridge. They went straight for the bridge.

"And we slowly came up to them, keeping our distance, and we saw that this car was flying up (the road). We got in front of that car to slow them down. I don't think they saw these deer," she said.

"We were driving slow by them. The buck was leading the whole time — then he just bolts straight east. The three doe followed him over," Denny Benyshek, another eyewitness narrated the tragic event and revealed that the entire incident took place within seconds.

Deer suicide
A whitetail deer stands among the trees on November 27, 2017 near Banff, Alberta DON EMMERT/AFP/Getty Images

Animal suicide is still a widely debatable subject but scientist tend to refute the phenomenon. Antonio Preti, a psychiatrist at the University of Cagliari in Italy, claims to have studied over 1000 books on the subject but found no evidence of any animal attempting suicide in the wild.

According to a research by Edmund Ramsden and medical historian Duncan Wilson of the University of Manchester, published in the Oxford University Press, animal activists tend to humanise animal emotions and try to impose their mass death as a psychological phenomenon.

In their report, they quoted Henry Maudsley, the pioneering British psychiatrist of the 20th century, who had said that it was possible that an animal "in a state of excitement or delirium from pain and illness may make a frantic rush that issues in its death, just as a human being may do; but this is quite a different thing to a distinctly conceived and deliberately perpetuated suicide".

Meanwhile, The state natural resources department conducts a deer harvest season every year in December that leads to a rise in their number in the region. Known as the annual shotgun season, this year a total of 76,204 deer have been reported in the state.