- Macaws@ (26)
- Magnoliopsida@ (6,881)
- Maize@ (3)
- Mammals@ (2,149)
- Manatees@ (14)
- Mandarin Duck@ (5)
- Mandrills@ (52)
- Mantellas@ (10)
- Mantids@ (26)
- Mantis Shrimps@ (9)
- Maples@ (51)
- Marsupials@ (151)
- Mayflies@ (11)
- Meerkat@ (21)
- Millipedes@ (6)
- Mimic-Thrushes@ (17)
- Minke Whale@ (5)
- Mites@ (83)
- Moles@ (19)
- Molluscs@ (213)
- Mongoose@ (18)
- Monitor Lizards@ (28)
- Monocots@ (1,766)
- Monotremes@ (10)
- Moose@ (52)
- Mosquitoes@ (23)
- Mosses@ (270)
- Moths@ (238)
- Motmots@ (1)
- Mountain Lions@ (11)
- Muridae@ (79)
- Mushrooms@ (1,262)
- Mustelids@ (105)
- Myxomycota@ (28)
