Ricketts Glen State Park was named part of an Important Mammal Area because it "support[s] critical habitat for a wide range of mammals"; Pennsylvania has 64 wild mammal species.
The park has an extensive forest cover of hemlock-filled valleys and hardwood-covered mountains, which makes it a habitat for big woods wildlife.
Animals such as white-tailed deer, black bear, red and gray squirrels, porcupine, and raccoon are seen fairly regularly.
Less common creatures include beaver, bobcat, coyote, fisher,  mink, muskrat, red fox, and river otter.
In addition to mammals, Ricketts Glen is also known for its wild turkeys, wild flowers, butterflies, dragonflies, and the occasional timber rattlesnake.

White-tailed deer became locally extinct on Ricketts' land by 1912, mirroring the sharp decline in Pennsylvania's deer population from overhunting and loss of habitat in the late 19th and early 20th centuries.
The state imported nearly 1,200 white-tailed deer from Michigan between 1906 and 1925 to re-establish the species throughout Pennsylvania, and Ricketts brought deer to the area of the park in 1914.
Pennsylvania's deer population rebounded from roughly one thousand in 1905 to roughly one million in 1928.
Deer are now one of the most numerous mammals in the park, and their overbrowsing threatens development of trees and plants there.
The deer eat most of the saplings and shrubs before they can reach their full size, which reduces the number of low lying plants many birds use for shelter.
The white-tailed deer became the official state animal in 1959.
By 2001, deer populations had increased to the point where it was feared that "Pennsylvania is losing its vegetative diversity from deer over-browsing".

Other locally extinct mammals in Pennsylvania include bison, grey wolf, lynx, marten, moose, mountain lion, and wolverine.
Beaver and river otter have been successfully reintroduced.
In 1995 and 1996, 39 fishers were released in the State Game Lands adjoining the park, and breeding populations appear to have been reestablished.
The coyote seems to have come to the state in the 1930s.
Black bear and wild turkey populations were also severely affected by overhunting and loss of habitat; the recovery of their populations in the 20th century has been "aided by the re-growth of the eastern deciduous forest".
Bears prefer a mixed forest of hickory and oak with an understory of shrubs such as blueberry and laurel; they use patches of coniferous forest for cover during the winter months.
Ricketts Glen State Park was named part of an Important Mammal Area because it "support[s] critical habitat for a wide range of mammals"; Pennsylvania has 64 wild mammal species. The park has an extensive forest cover of hemlock-filled valleys and hardwood-covered mountains, which makes it a habitat for big woods wildlife. Animals such as white-tailed deer, black bear, red and gray squirrels, porcupine, and raccoon are seen fairly regularly. Less common creatures include beaver, bobcat, coyote, fisher,  mink, muskrat, red fox, and river otter. In addition to mammals, Ricketts Glen is also known for its wild turkeys, wild flowers, butterflies, dragonflies, and the occasional timber rattlesnake.
White-tailed deer became locally extinct on Ricketts' land by 1912, mirroring the sharp decline in Pennsylvania's deer population from overhunting and loss of habitat in the late 19th and early 20th centuries. The state imported nearly 1,200 white-tailed deer from Michigan between 1906 and 1925 to re-establish the species throughout Pennsylvania, and Ricketts brought deer to the area of the park in 1914. Pennsylvania's deer population rebounded from roughly one thousand in 1905 to roughly one million in 1928. Deer are now one of the most numerous mammals in the park, and their overbrowsing threatens development of trees and plants there. The deer eat most of the saplings and shrubs before they can reach their full size, which reduces the number of low lying plants many birds use for shelter. The white-tailed deer became the official state animal in 1959. By 2001, deer populations had increased to the point where it was feared that "Pennsylvania is losing its vegetative diversity from deer over-browsing".
Other locally extinct mammals in Pennsylvania include bison, grey wolf, lynx, marten, moose, mountain lion, and wolverine. Beaver and river otter have been successfully reintroduced. In 1995 and 1996, 39 fishers were released in the State Game Lands adjoining the park, and breeding populations appear to have been reestablished. The coyote seems to have come to the state in the 1930s. Black bear and wild turkey populations were also severely affected by overhunting and loss of habitat; the recovery of their populations in the 20th century has been "aided by the re-growth of the eastern deciduous forest". Bears prefer a mixed forest of hickory and oak with an understory of shrubs such as blueberry and laurel; they use patches of coniferous forest for cover during the winter months.
Ricketts Glen State Park