A turtle glides through the water at the Texas State Aquarium in Corpus Christi. Original image from Carol M.… Free Image from public domain license 
Lions in the grass at the Wild Animal Sanctuary near Keenesburg, Colorado. Original image from Carol M. Highsmith’s… Free Image from public domain license 
A red fox prowls for voles, hidden beneath the snow, in Yellowstone National Park in the western U.S. state of Wyoming.… Free Image from public domain license 
An up-close look at a giraffe at the Gladys Porter Zoo in Brownsville, Texas. Original image from Carol M. Highsmith’s… Free Image from public domain license 
A red fox prowls for voles, hidden beneath the snow, in Yellowstone National Park in the western U.S. state of Wyoming.… Free Image from public domain license 
An endangered green sea turtle is released into the Mosquito Lagoon. Original from NASA. Digitally enhanced by rawpixel. Free Image from public domain license 
A bighorn sheep in Colorado National Monument, a preserve of vast plateaus, canyons, and towering monoliths in Mesa County… Free Image from public domain license 
A mixed herd of wild and domesticated horses frolics on the Ladder Livestock ranch, at the Wyoming-Colorado border. Original… Free Image from public domain license 
Giant pandas, the star attraction at the Smithsonian Institution's National Zoo. Original image from Carol M.… Free Image from public domain license 
A mixed herd of wild and domesticated horses frolics on the Ladder Livestock ranch, at the Wyoming-Colorado border. Original… Free Image from public domain license 
Seahorse at The Monterey Bay Aquarium in Monterey, California. Original image from Carol M. Highsmith’s America… Free Image from public domain license 
A mixed herd of wild and domesticated horses frolics on the Ladder Livestock ranch, at the Wyoming-Colorado border. Original… Free Image from public domain license 
A mixed herd of wild and domesticated horses frolics on the Ladder Livestock ranch, at the Wyoming-Colorado border. Original… Free Image from public domain license 
Lions at The Montgomery Zoo in Oak Park. Original image from Carol M. Highsmith’s America, Library of Congress… Free Image from public domain license 
Coiled rattlesnake in brush outside San Marcos, Texas. Original image from Carol M. Highsmith’s America, Library of… Free Image from public domain license 
American bison, or buffaloes, in Yellowstone National Park in the northwest corner of Wyoming. Original image from Carol M.… Free Image from public domain license 
A fat and sassy prairie dog on the grounds of Devil's Tower National Monument in Crook County, Wyoming. Original image from… Free Image from public domain license 
Young calf standing in a field in rural Alabama. Original image from Carol M. Highsmith’s America, Library of Congress… Free Image from public domain license 
Peacock (1925 - 1936) by Ohara Koson (1877-1945). Original from The Rijksmuseum. Digitally enhanced by rawpixel. Free Image from public domain license 
Yearlings on a ranch in Red River County near Detroit, Texas. Original image from Carol M. Highsmith’s America, Library… Free Image from public domain license 
Giraffe couple at The Montgomery Zoo in Oak Park. Original image from Carol M. Highsmith’s America, Library of Congress… Free Image from public domain license 
Horse in Orick, California. Original image from Carol M. Highsmith’s America, Library of Congress collection. Digitally… Free Image from public domain license 
Northern California elk. Original image from Carol M. Highsmith’s America, Library of Congress collection. Digitally… Free Image from public domain license 
Cover of A history of the earth and animated nature (1820) by Oliver Goldsmith (1730-1774). Digitally enhanced from our own… Free Image from public domain license 
Tiger at the Wild Animal Sanctuary, near Keenesburg, Colorado. Original image from Carol M. Highsmith’s America… Free Image from public domain license 
Holstein dairy cows at the Dunnum Family's Top of the Town dairy farm near Westby in Vernon County, Wisconsin. Original image… Free Image from public domain license 
Mules gaze from opposite directions in rural Clayton County, Iowa. Original image from Carol M. Highsmith’s America… Free Image from public domain license 
Mule deer gather on a snowy hillside in Sweetwater County, Wyoming. Original image from Carol M. Highsmith’s America… Free Image from public domain license 
Horse within a lovely meadow in the Lyndon B. Johnson National Historical Park in Johnson City, Texas. Original image from… Free Image from public domain license 
Cattle at Dye Creek Ranch near Red Bluff, California. Original image from Carol M. Highsmith’s America, Library of… Free Image from public domain license 
Giraffe at The Montgomery Zoo in Oak Park. Original image from Carol M. Highsmith’s America, Library of Congress… Free Image from public domain license 
Hogs live out their last days in the "finishing shed," where they are grouped by weight to give smaller animals a fair chance… Free Image from public domain license 
Baluga Whales at Mystic Aquarium. Original image from Carol M. Highsmith’s America, Library of Congress collection.… Free Image from public domain license 
White Bengal tiger at the Montgomery Zoo, it was established in 1920 as part of Oak Park. Original image from Carol M.… Free Image from public domain license 
Chimpanzee at the North Carolina Zoological Park in Asheboro, North Carolina. Original image from Carol M. Highsmith’s… Free Image from public domain license 
Horses graze in the pasture at the A Bar A guest ranch, near Riverside, Wyoming. Original image from Carol M.… Free Image from public domain license 
Parrot poses on a tree in Florida. Original image from Carol M. Highsmith’s America, Library of Congress collection.… Free Image from public domain license 
Sheep at the Ladder Livestock Ranch, which is based across the highway from Colorado in Carbon County, Wyoming. Original… Free Image from public domain license