MAMMALS OF MARYLAND 



9 



closest resemblance between two sections is that between the Western 

 Shore and the Piedmont. Surprisingly, the two Coastal Plain sections, 

 the Western Shore and the Eastern Shore, show slightly less resem- 

 blance to each other. This is probably due to the isolating effect of 

 the Chesapeake Bay on the Eastern Shore. 



The percentages show clearly that the Allegheny Mountain and 

 E-idge and Valley sections have close faunal resemblance, and that 

 as a unit they stand somewhat apart from the three eastern sections. 

 Thus, while the resemblance ratio of the Eastern Shore to the Western 

 Shore is 90 percent, and that of the Western Shore to the Piedmont 

 is 92 percent, the Piedmont has a resemblance to the neighboring Ridge 

 and Valley section of only 83 percent. The resemblance of the Ridge 

 and Valley to its neighboring Allegheny Mountain section returns 

 to 87 percent, indicating that these two sections differ to some extent 

 from the three eastern sections, which in turn appear to form a 

 closely allied mammalian fauna unit. Therefore, the most strongly 

 marked division with regard to mammal distribution in Maryland is 

 that between the gently rolling Piedmont of Montgomery, Howard, 

 Baltimore, Harford, Carrol], and eastern Frederick Counties and the 

 upland Blue Ridge Mountains (Ridge and Valley section) to the west 

 in Washington and western Frederick Counties. 



Taken as a whole, Maryland's mammal fauna seems to be more 

 northern than southern in origin. Only a few distinctly southern 

 species (represented usually by small numbers of indi\d duals) reach 

 Maryland. Some of these are Reithrodontomys humulis, 8 or ex longi- 

 rostris^ and Spilogale putorim. On the other hand, a number of 

 distinctly northern species reach south to Maryland {Sorex cinereu^, 

 Mustela ermine a. Lepus americanus. T amiasciurus hudsonicus^ and 

 a number of others) and extend even farther south, particularly in 

 the Appalachian Mountains, where many of them range as far south 

 as North Carolina and Tennessee. 



The following keys employ external and easily observable or measur- 

 able characters when possible. In a few instances it has been necessary 

 to resort to dental characters when external ones were not sufficiently 

 marked to separate forms. The keys are designed for use on adult 

 animals only. 



Key to the Orders of Maryland Land Mammals 



KEYS 



la. Forelimbs modified as wings 



h. Forelimbs not modified as wings. 



2a. Feet provided with hoofs 



h. Feet provided with claws 



Chiroptera (bats) 

 2 



Artiodactyla (even-toed hoofed mammals) 



3 



