Colleen Chance, a tribal housing authority employee on the reservation, located east of Pendleton, said the cries were first reported last month and there are many theories as to what animals are making the sounds, The (Portland) Oregonian reported Monday.
"It's kind of spooky," she said. "Some say it's foxes, some say it's a female coyote and some say it's Sasquatch. I don't know what it is."
Some members of the Umatilla, Walla Walla and Cayuse tribes said they are convinced the sounds are coming from the legendary ape-like humanoid Sasquatch, or Bigfoot. Marcus Luke, a housing authority home ownership counselor and follower of the Washat, or Seven Drums, religion, said Bigfoot is part of the tribal tradition and spiritual beliefs.
However, Carl Sheeler, wildlife program manager for the tribes, said there are several more likely culprits, including cougars, that the never-verified Big Foot.
"When they are breeding, it is absolutely hair-raising," he said of the cougars' mating calls.
"And the first time a person hears a fox calling in the night, kind of echoing around the canyons, it raises the hair on the back of your neck," Sheeler said. "That wetland is a perfect place to have an echoing call sound eerie."