By Stephanie Keith OLYMPIC PENINSULA, Wash. (Reuters) – Howling hounds picked up a cougar’s scent and led researchers deep into the forest, where the steep hills were covered with cedars and ferns dusted with snow. The dogs chased Lilu, an 82-pound (37-kg) cougar whose collar needed a new battery, up a tree. After being plunked by a tranquilizer dart, the groggy cat climbed down and went to sleep. The team was able to swap her collar, examine Lilu, and then inject her with a drug to wake her. It was part of a day’s work for the Olympic Cougar Project, a partnership between a coalition of Nativ…