Wolves from the Snake River Pack attacked and severely injured a calf Monday near Freezeout Saddle in Wallowa County, the Oregon Department of Fish and Wildlife (ODFW) said Wednesday.
It was the first confirmed case of wolves from that pack attacking livestock.
A rancher who was checking on his cattle on a Forest Service grazing allotment on Monday told ODFW investigators that he saw one cow running down a hill, and a short time later he saw four wolves just uphill from where the cow had been.
The rancher said he scared the wolves away by making loud noises.
On Tuesday morning the rancher returned to the site and found one injured calf.
That evening ODFW officials examined the 250-pound calf and found numerous deep bite wounds to the rear legs.
"Several of the wounds on the hind right leg showed clear evidence of opposing teeth which indicated a large jaw clamping over the leg," according to an ODFW report.
"Multiple, gaping holes in the hide and muscle tissues appeared to be from large canine teeth."
Data from GPS collars that two Snake River Pack wolves are wearing show that those two wolves were in the area where the calf was found, at the suspected time of the attack, either late Monday or early Tuesday.
There is "adequate evidence to confirm thisincident as a wolf depredation," according to ODFW.
ODFW biologists captured and collared the two wolves on March 14, 2013.
The agency estimates that the Snake River Pack, at the end of 2012, consisted of seven wolves, including one breeding pair.
There are seven confirmed wolf packs in Oregon, all in the northeast corner of the state. There are no confirmed packs in Baker County.