Scales help protect this lizard from harsh weather and predators. The marine iguana (Amblyrhynchus cristatus) is unique to the Galápagos Islands. Despite its scaly shield, the species is still considered vulnerable to extinction because of non-native rats, feral cats, and dogs that feed on iguana eggs and young.
The crest of a Victoria crowned pigeon (Goura victoria) creates a bouquet of gray and white. Found in tropical regions and related to the Dodo (Raphus cucullatus), the Victoria crowned pigeon features a crest fringed in white. The males display their feathery headdresses to attract a mate.
Snapped off the coast of Borneo, these iridescent green scales armor a parrotfish (Scarus sp.). The evolutionary link between feathers and scales is evident on developing bird embryos, which are scattered with disks of cells called placodes. Some of these cells grow into scales, such as the ones that cover a chicken's legs, while others turn into feathers.
A wandering albatross (Diomedea exulans) contracts its wings during a mating ritual on South Georgia Island, Antarctica. This arduous traveler has one of the greatest known wingspans of any bird, measuring up to 11.5 feet (3.5 meters), and has been recorded flying 500 miles (805 kilometers) in a single day.
Orange spots mark the fin of fish photographed in Lake Baikal, Siberia, Russia.
Found in Southeast Asia, the male great argus pheasant (Argusianus argus) displays these dots on its feathers during courtship. Its plumage radiates around its head, like a peacock's. Beyond attracting a mate, feathers are used for insulation, flight, and, in some cases, to help a bird hunt and evade predators.
The feathers of a wedge-tailed eagle (Aquila audax) form a gauzy screen in Alice Springs Desert Park in Australia's Northern Territory. From a central feather vane sprout hundreds of filaments called barbs. The barbs in turn sprout other, smaller filaments, some with grooves and some with hooks that clasp the barbs together like Velcro, allowing the bird to fly.
A fan of black-chinned sparrow (Spizella atrogularis) feathers captures the light. When birds pull their feathers apart to clean them, the barb filaments simply zip back together by themselves.