Monkey
Mink
Mouse
Mini pig
Macaque
Macaw
Mackerel
Mackerel shark
Madagascar hissing roach
Maggot
Magpie
Mahogany glider
Maiasaura
Majungatholus
Mako shark
Malamute
Mallard
Maltese dog
Mamba
Mamenchisaurus
Mammoth
Man
Manatee
Mandarin duck
Mandrill
Mangabey
Mangrove gerygone
Mangrove honeyeater
Mangrove jack
Manta
Manta Ray
Mantis
Mantis ray
Manx cat
Maori wrasse
Mara (South American rodent)
Marabou
Marbled Murrelet
Mare
Marlin
Marmoset
Marmot
Marsupial mole
Marten
Martin
Masked plover
Masked booby
Massasauga
Massospondylus
Mastiff
Mastodon
May beetle
Maybug
Mayfly
Meadowlark
Meadow pipit
Meerkat
Megalosaurus
Megaraptor
Merganser
Merlin
Metallic skink
Microvenator
Midge
Milksnake
Millipede
Miner bird
Miniature poodle dog
Miniature schnauzer dog
Minibeast
Mink
Minnow
Mistletoebird
Mitchell's Hopping mouse
Mite
Moa
Mockingbird
Mole
Mollies
Mollusk
Molly
Monarch
Mongoose
Monitor lizard
Monkey
Monkfish
Monoclonius
Montanoceratops
Moon wrasse
Moorhen
Moose
Moray
Moray eel
Mosasaur
Mosquito
Moth
Motmot
Mountain beaver
Mountain Brushtail possum
Mountain cat
Mountain goat
Mountain lion
Mountain Pygmy possum
Mountain skink
Mouse
Mousebird
Mouse deer
Mud puppy
Mudskipper
Mule
Mule deer
Mulga parrot
Mulga snake
Mulgara
Mullet
Muntjac
Murray cod
Murray turtle
Murrelet
Mussel
Musk lorikeet
Musk duck
Musk ox
Muskrat
Musky rat-kangaroo
Mussaurus
Mustang
Mynah bird