- Sacred Kingfisher
- Saddleback Caterpillar Moth
- Saffron Finch
- Saint Andrew's Cross Spider
- Salema Porgy
- Sally Lightfoot Crab
- Salt Marsh Moth
- Saltwater Crocodile
- San Diego Dorid
- Sand Lizard
- Sanderling
- Sandhill Crane
- Sandwich Tern
- Sardinian Warbler
- Satin Bowerbird
- Satyr Comma
- Savannah Sparrow
- Say's Phoebe
- Sayaca Tanager
- Scaly-breasted Munia
- Scarce Chaser
- Scarce Copper
- Scarce Swallowtail
- Scarce Tortoiseshell
- Scarlet Percher
- Scarlet Robin
- Scarlet Skimmer
- Scarlet Tanager
- Scarlet Tiger
- Scarlet-rumped Tanager
- Scissor-tailed Flycatcher
- Scolia hirta
- Scorched Carpet
- Scotch Argus
- Sculptured Resin Bee
- Seaside Dragonlet
- Sedge Warbler
- Semipalmated Plover
- Semipalmated Sandpiper
- Setaceous Hebrew Character
- Seven-spotted Lady Beetle
- Shaded Broad-bar
- Shadow Darner
- Sharp-shinned Hawk
- Shikra
- Shiny Cowbird
- Short-billed Dowitcher
- Short-billed Gull
- Short-eared Owl
- Short-tailed Blue
- Short-tailed Hawk
- Short-toed Snake-Eagle
- Short-toed Treecreeper
- Short-winged Meadow Katydid
- Short-winged Rice Grasshopper
- Shuttle-shaped Dart
- Siberian Stonechat
- Sigmoid Prominent
- Signal Crayfish
- Silk-Button Spangle Gall Wasp
- Silver Garden Orbweaver
- Silver Gull
- Silver Υ
- Silver-ground Carpet
- Silver-spotted Skipper
- Silver-spotted Tiger Moth
- Silver-studded Blue
- Silver-washed Fritillary
- Silvereye
- Silvery Blue
- Silvery Checkerspot
- Singing Honeyeater
- Single-dotted Wave
- Six-lined Racerunner
- Six-spot Burnet
- Six-spotted Fishing Spider
- Six-spotted Orbweaver
- Six-spotted Tiger Beetle
- Six-spotted Zigzag Ladybird
- Skiff Moth
- Skimming Bluet
- Slaty Skimmer
- Sleepy Orange
- Slender Skimmer
- Slender Spreadwing
- Sloe Bug
- Small Blue
- Small Copper
- Small Dusty Wave
- Small Elephant Hawkmoth
- Small Emperor Moth
- Small Engrailed
- Small Fan-footed Wave
- Small Gold Grasshopper
- Small Grey
- Small Heath
- Small Magpie
- Small Milkweed Bug
- Small Phigalia Moth
- Small Phoenix
- Small Pincertail
- Small Quaker
- Small Red-eyed Damselfly
- Small Skipper
- Small Tortoiseshell
- Small Transverse Ladybird Beetle
- Small White
- Small-eyed Sphinx
- Smallmouth Bass
- Smew
- Smooth Newt
- Smooth Snake
- Smooth-billed Ani
- Snail Kite
- Snakelocks anemone
- Snow Bunting
- Snow Goose
- Snowberry Clearwing
- Snowshoe Hare
- Snowy Egret
- Snowy Owl
- Snowy Plover
- Snowy Urola Moth
- Social Flycatcher
- Soft-shelled Clam
- Solitary Sandpiper
- Song Sparrow
- Song Thrush
- Sonoran Bumble Bee
- Sooty Copper
- Sora
- South American Sea Lion
- Southern Alligator Lizard
- Southern Black Widow
- Southern Carpenter Bee
- Southern Darter
- Southern Dogface
- Southern Emerald
- Southern Flannel Moth
- Southern Flat Oyster
- Southern Green Stink Bug
- Southern Hawker
- Southern House Spider
- Southern House Wren
- Southern Lapwing
- Southern Leopard Frog
- Southern Monarch
- Southern Oak Bush-cricket
- Southern Red Bishop
- Southern Rock Agama
- Southern Skimmer
- Southern Toad
- Southern Two-lined Salamander
- Southern White Admiral
- Southern Yellowjacket
- Spangled Skimmer
- Spanish Slug
- Sparganothis Fruitworm Moth
- Sparkling Violetear
- Speckled Bush-cricket
- Speckled Wood
- Speckled Yellow
- Spectacled Caiman
- Spectacled Tyrant
- Spicebush Swallowtail
- Spilostethus saxatilis
- Spined Micrathena
- Spiny Oak-slug Moth
- Spiny Softshell
- Spiny Toad
- Spinybacked Orbweaver
- Spongy Moth
- Spongy Oak Apple Gall Wasp
- Spot-legged Tree Frog
- Spot-winged Glider
- Spotless Lady Beetle
- Spotless Starling
- Spotted Apatelodes Moth
- Spotted Beet Webworm Moth
- Spotted Cucumber Beetle
- Spotted Dorid
- Spotted Dove
- Spotted Firebug
- Spotted Flycatcher
- Spotted Fritillary
- Spotted Grass Moth
- Spotted Hyena
- Spotted Lanternfly
- Spotted Longhorn Beetle
- Spotted Orbweaver
- Spotted Pardalote
- Spotted Pink Lady Beetle
- Spotted Porcupinefish
- Spotted Redshank
- Spotted Salamander
- Spotted Sandpiper
- Spotted Spreadwing
- Spotted Sulphur
- Spotted Towhee
- Spotted Tussock Moth
- Spring Epistrophe
- Spring Fishfly
- Spring Harvestman
- Spring Peeper
- Springtime Dung Beetle
- Springwater Dancer
- Spruce Grouse
- Squacco Heron
- Square-spot Rustic
- Squirrel Tree Frog
- Steller Sea Lion
- Steller's Jay
- Steppe Grasshopper
- Stilt Sandpiper
- Stock Dove
- Straw Dot
- Straw Underwing
- Straw-barred Pearl
- Straw-necked Ibis
- Strawberry Poison Dart Frog
- Strawberry Root Weevil
- Streak-backed Oriole
- Streaked Flycatcher
- Stream Bluet
- Striated Heron
- Striated Pardalote
- Stripe-eyed Lagoon Fly
- Stripe-legged Robber Fly
- Striped Bark Scorpion
- Striped Fishing Spider
- Striped Hawkmoth
- Striped Lynx Spider
- Striped Millipede
- Striped Shore Crab
- Striped Skunk
- Subterranean Dart
- Subtropical Lady
- Sulphur-crested Cockatoo
- Summer Azure
- Summer Chafer
- Summer Fishfly
- Summer Tanager
- Sun Fly
- Sunburst Anemone
- Superb Dog-day Cicada
- Superb Fairywren
- Surf Scoter
- Surinam Cockroach
- Swainson's Hawk
- Swainson's Thrush
- Swallow-tailed Kite
- Swamp Cicada
- Swamp Milkweed Leaf Beetle
- Swamp Sparrow
- Swamp Wallaby
- Swan Moth
- Sweetfern Geometer Moth
- Swift Setwing
- Swift Woodlouse
- Swinhoe's White-eye
- Sycamore Moth
- Sycamore Tussock Moth
- Sylvan Jumping Spider
- Syrian Woodpecker