- Abracris flavolineata
- Acanthocephala terminalis
- Acmon Blue
- Acorn Woodpecker
- Adanson's House Jumper
- Adder
- Adonis Blue
- Aesculapian Snake
- African Fish-Eagle
- African Giant Snail
- African Sacred Ibis
- Aggregating Anemone
- Agile Frog
- Agreeable Tiger Moth
- Ailanthus Webworm Moth
- Alder Leaf Beetle
- Alder Spittlebug
- Alfalfa Plant Bug
- Allen's Hummingbird
- Alpine Marmot
- Alpine Newt
- Altamira Oriole
- Amazon Kingfisher
- Ambiguous Moth
- American Alligator
- American Avocet
- American Barn Owl
- American Beaver
- American Bird Grasshopper
- American Bison
- American Bittern
- American Black Bear
- American Black Duck
- American Bullfrog
- American Bumble Bee
- American Carrion Beetle
- American Cockroach
- American Coot
- American Copper
- American Copper Underwing
- American Crow
- American Dagger
- American Dipper
- American Dog Tick
- American Flamingo
- American Giant Water Bug
- American Goldfinch
- American Green Crab Spider
- American Herring Gull
- American Idia Moth
- American Kestrel
- American Lady
- American Lappet Moth
- American Mink
- American Nursery Web Spider
- American Oystercatcher
- American Pelecinid Wasp
- American Pika
- American Pipit
- American Red Squirrel
- American Redstart
- American Robin
- American Rubyspot
- American Snout
- American Toad
- American Tree Sparrow
- American White Pelican
- American Wigeon
- American Winter Ant
- American Woodcock
- Angle Shades
- Angulate Tortoise
- Angulose Prominent
- Anhinga
- Anise Swallowtail
- Anna's Hummingbird
- Ant Damselbug
- Apollo
- Appalachian Brown
- Apple Blossom Beetle
- Apple Looper
- Arabesque Orbweaver
- Arboreal Salamander
- Arched Hooktip Moth
- Arcigera Flower Moth
- Arctic Green Sea Urchin
- Arctic Loon
- Arctic Tern
- Argentine Ant
- Argentine Black-and-white Tegu
- Arizona Mantis
- Armyworm Moth
- Arrowhead Orbweaver
- Ash Cicada
- Ash-black Slug
- Ash-throated Flycatcher
- Ashy Gray Lady Beetle
- Ashy Mining Bee
- Asian Clam
- Asian Common Toad
- Asian Glossy Starling
- Asian Green Bee-eater
- Asian Honey Bee
- Asian House Gecko
- Asian Koel
- Asian Lady Beetle
- Asian Oak Weevil
- Asian Openbill
- Asian Painted Frog
- Asian Tiger Mosquito
- Asian Tit
- Asian Tramp Snail
- Asian Weaver Ant
- Aspen Serpentine Leafminer Moth
- Atala
- Atlantic Beadlet Anemone
- Atlantic Blue Crab
- Atlantic Blue Tang
- Atlantic Dogwhelk
- Atlantic Ghost Crab
- Atlantic Horseshoe Crab
- Atlantic Puffin
- Atlantic Ribbed Mussel
- Atlantic Rock Crab
- Atlantic Sand Crab
- Atlantic Sergeant Major
- Atlantis Fritillary
- Australasian Darter
- Australasian Figbird
- Australasian Grebe
- Australasian Swamphen
- Australian Bluetail
- Australian Brushturkey
- Australian Cockroach
- Australian Common Crow
- Australian Golden Orbweaver
- Australian Ibis
- Australian King Parrot
- Australian Magpie
- Australian Painted Lady
- Australian Pelican
- Australian Pug Moth
- Australian Water Dragon
- Australian Wood Duck
- Autumn Meadowhawk
- Azure Bluet
- Azure Damselfly
- Azure-winged Magpie