Thirty-four species of mammals call the park home. The predominant landscape of the park is rolling fields and meadows providing ideal habitat for the many rodent species, which compose most of the park’s mammal population. Most of these rodents are terrestrial or burrowing animals such as the species of voles, shrews, and mice. Both red and gray foxes take advantage of the population of small mammals as a food source in addition to their diets of grains, fruits, and nuts. The many acres of woodlots and forested land provide habitat to arboreal rodents such as Eastern chipmunks, Eastern gray squirrels, and Southern flying squirrels. Within these same woods, larger mammal species such as white-tailed deer, raccoons, skunks, and opossums reside.
During the 1980s, Gettysburg NMP had an overabundance of deer, estimated at 102 deer per square forested mile. By 1995 the population had grown to a density of 325 deer per square forested mile. The over abundance of deer had a negative impact, through intensive browsing, on forest and forest understory vegetation, crops, and vehicular accidents in the park. As a result, regeneration of some forest species, representative of the Civil War era in the park, where displaced or prohibited from reaching the next growth stage. It also became more difficult for National Park Service staff to maintain the agricultural characteristics of the1863 landscape. Beginning in the early 1990s, the NPS began to gather data about controlling the deer population. In 1995 the park signed a Record of Decision and released an Environmental Impact Statement and Management Plan for managing the herd through a combination of controlled harvesting and cooperative management. The EIS set a deer density goal at 25 deer per square forested mile. Today the park strives to maintain an accepted ecological balance between deer and surrounding vegetation communities. Currently the park has an estimated 40 deer per forested square mile, an 80% decrease in the population, but not yet at the recommended deer density goal.
The National Park Service also recently monitored bat diversity in the park through summer mist netting and surveys of historic structures for roost sites. Six bat species were identified ranging from the little Eastern pipistrels to larger bat species such as Hoary bats. A state candidate bat species, the Northern myotis, was also recorded through mist netting. Another bat survey is planned for the summer of 2004.
List of mammals found in park:
1. Virginia Opossum
2. Masked Shrew
3. Maryland Shrew
4. Least Shrew
5. Short-tailed Shrew
6. Northern Long-eared Myotis
7. Little Brown Myotis
8. Eastern Pipistrel
9. Red Bat
10. Big Brown Bat
11. Hoary Bat
12. Raccoon
13. Black Bear
14. Long-tailed Weasel
15. Mink
16. Eastern Spotted Skunk
17. Striped Skunk
18. Red Fox
19. Gray Fox
20. Bobcat
21. Woodchuck
22. Eastern Chipmunk
23. Eastern Gray Squirrel
24. Southern Flying Squirrel
25. Beaver
26. White-footed Mouse
27. Deer Mouse
28. Meadow Vole
29. Muskrat
30. Norway Rat
31. House Mouse
32. Meadow Jumping Mouse
33. Eastern Cottontail
34. White-tailed Deer
