The park also provides habitat for many species (like the Roosevelt elk) that are native only to the Pacific Northwest coast. As a result, scientists have declared it a biological reserve and study its unique species to better understand how plants and animals evolve. The park is home to sizable populations of black bears and black-tailed deer. The park also has a noteworthy cougar population, numbering about 150. Mountain goats were accidentally introduced into the park into the 1920s and have caused much damage on the native flora. The NPS has activated management plans to control the goats.