A horrified couple watched the moment a herd of deer leapt to their deaths from a 30ft bridge.

Video footage shows a stag sprinting across the road and jumping straight over the bridge's sidewall, closely followed by three does.

The extraordinary spectacle was captured on camera by Catherine Veerhusen as her husband drove along the bridge in Cedar Rapids, Iowa.

"I've never seen anything like this," she told the Des Moines Register. "No words, no words.

"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."

The does were all later found dead at the foot of the bridge, although the stag had disappeared.

Ron Lane, a conservation officer with the Iowa Department of Natural Resources in Linn County, believes the herd were unfamiliar with the area and were panicked, possibly by a hunter.

"The bridge there is brand new," he said. "I'm guessing the deer aren't used to that, with all of the construction going on."

Iowa is in the midst of its deer hunting season, and Mr Lane said the ill-fated animals could have been fleeing the sounds of shotguns.

He added: "It sounds like with they were just trying to run across and didn't know where to go."