Mauritian tomb bat 
Meadow jumping mouse 
Meadow vole 
Mearns coyote 
Meerkat 
Merriams chipmunk 
Mesic Four-striped Grass Rat 
Mexican gray squirrel 
Mexican Hairy Dwarf Porcupine 
Mexican Wolf 
Middle East blind mole-rat 
Midget buffalo 
Milne-Edwards sifaka 
Milne-Edwards sportive lemur 
Minke whale 
Minute fruit bat 
Mishmi takin 
Mona monkey 
Monk saki 
Montane guinea pig 
Moose 
Mountain cottontail 
Mountain coyote 
Mountain Gazelle