By Laura Zuckerman
SALMON, Idaho (Reuters) - Thirty pronghorns, close cousins to antelope, died while crossing a frozen river in south central Idaho, in a very rare event for the sure-footed mammals, state wildlife managers said Tuesday.
About 500 pronghorns, which look like small deer and are famed for being the fastest land animal in North America, were seeking to cross the frozen Snake River near a wildlife refuge in Idaho on Sunday when part of the herd began slipping and falling on the ice, according to the Idaho Department of Fish and Game.
Roughly 200 of the pronghorns, so named for the short, forked horns on their heads, had successfully crossed the stream before a group of 47 became stranded on the ice, prompting hundreds of others to turn back to shore.
Idaho wildlife managers mounted a rescue mission on Monday, by which time just 36 pronghorns remained on the ice sheet. Ten of those had been killed and partially eaten by coyotes, 20 were so severely injured that they had to be euthanized on the spot and six survivors were taken by airboat to shore and released, Fish and Game officials said.
Although deer and elk periodically die seeking to cross frozen waterways, such incidents are rare when it comes to pronghorns, state wildlife officials said.
"I have never seen anything like it in my 26-year career," Daryl Meints, regional Idaho Fish and Game wildlife manager, said in a statement.
The agency's Gregg Losinski said pronghorns have traditionally been called antelope even though they are technically just a relative to both antelope and goats.
Pronghorns, which are subject to regulated hunting in Idaho and elsewhere, are nicknamed "speed goats" for a swiftness of hoof that can see them reach speeds of nearly 60 miles per hour (97 kph), said Losinski.
(Reporting by Laura Zuckerman; Editing by Dan Whitcomb and Sandra Maler)