Sheriff Jim Alderden says everything investigators have found is consistent with the behavior of a mountain lion, a clever animal that buries its prey.
Jaryd was three years old when the Littleton boy disappeared during a mountain hike in October 1999.
A jacket, pants, and shoes belonging to Jaryd turned up late last week in the Comanche Peak Wilderness Area west of Fort Collins.
Twenty or more searchers will return to the site on Saturday to search for remains, bones and a T-shirt that is still missing.
Authorities have steered clear of declaring the boy dead.
Jaryd's father, Allyn, said this morning he was holding out hope that his son was still alive.