Mountain lions in Washington state may be cutting down on traffic accidents by scaring deer away from roads, new research finds. Deer often avoid open spaces, including roads, when predators are nearby. The new study tracked wildlife across the Olympic Peninsula in Washington state, comparing collision data with photos from camera traps that revealed the whereabouts of mountain lions. The big cats, sometimes referred to as cougars or pumas, prey primarily on deer. Researchers found that where mountain lions were active, deer avoided roads.