Designing highway crossings to accommodate cougar passage through the Owens Valley fall under two typologies: highway bridge underpass and large box culvert. Both have advantages and disadvantages. Cougars prefer less open structures where they can remain hidden, so box culverts (with earthen substrate flooring) is the the option they respond to best. But cougar’s main food source in the valley, the mule deer, will not use a box culvert. Mule deer, like most ungulates, prefer overland crossings. They will, however, cross under a highway bridge underpass, as will cougars when following prey.