WINFIELD, Mo. – An effort by hundreds of townspeople, volunteers and National Guardsmen to hold back the Mississippi River failed Friday – undone by a burrowing muskrat.

The furry rodent dug a hole through the earthen levee in this eastern Missouri community, allowing water to penetrate the flood wall, which failed shortly before dawn.

"It's so disappointing," said Linda Wilmesherr as she peered through binoculars at water pouring through a gap that appeared to be 30 feet wide. "With all the guns in this county, couldn't we kill a muskrat?"

But within hours, defiant residents were mounting a new defense – a quickly constructed 4-foot-tall sandbag levee to protect 100 homes in the floodwaters' path.

"We're not quitting – the Army doesn't quit," said National Guard Col. Michele Melton. "That's why we're here – to try and save these people."

Many of the 720 residents of Winfield and people from nearby communities have spent the last several days helping the National Guard patch one trouble spot after another. In the end, their efforts were undone by an animal weighing no more than 5 pounds. Officials said the muskrat was either seeking food or building a den when it dug the hole that brought the levee down.

Elsewhere in Missouri, the flood news was improving. Canton, in far northeast Missouri, lifted its voluntary evacuation, with officials saying the levee protecting the town of 2,500 residents was sound and the river level was dropping.