Joel Sartore / Photo Ark / Zebra shark (Stegostoma tigrinum) juvenile, head portrait, Shark Reef Aquarium, Las Vegas, Nevada. Captive, occurs in Indo-Pacific.

Joel Sartore / Photo Ark / Zebra shark (Stegostoma tigrinum) juvenile, portrait, Shark Reef Aquarium, Las Vegas, Nevada. Captive, occurs in Indo-Pacific.

Joel Sartore / Photo Ark / Zebra shark (Stegostoma tigrinum) juvenile, portrait, Shark Reef Aquarium, Las Vegas, Nevada. Captive, occurs in Indo-Pacific.

Joel Sartore / Photo Ark / Zebra shark (Stegostoma tigrinum) juvenile, portrait, Shark Reef Aquarium, Las Vegas, Nevada. Captive, occurs in Indo-Pacific.

Joel Sartore / Photo Ark / Monarch butterfly (Danaus plexippus) portrait, from the wild, Bennet, Nebraska, USA.

Joel Sartore / Photo Ark / Monarch butterfly (Danaus plexippus megalippe) resting portrait, National Botanical Garden, Santo Domingo, Dominican Republic. Captive.

Joel Sartore / Photo Ark / Monarch butterfly (Danaus plexippus) portrait, from the wild, Sierra Chincua Mountains, Mexico.

Joel Sartore / Photo Ark / White-crowned sparrow (Zonotrichia leucophrys leucophrys) portrait, from the wild, Hudson, Wisconsin, USA.

Joel Sartore / Photo Ark / Baltimore oriole (Icterus galbula) male, portrait, from the wild, Hudson, Wisconsin, USA.

Joel Sartore / Photo Ark / Two Brown-necked parrots (Poicephalus fuscicollis fuscicollis) portrait, Loro Park, Tenerife. Captive, occurs in Africa.

Joel Sartore / Photo Ark / Mustard capped lorikeet (Trichoglossus meyeri) with mouth open, portrait, Loro Park, Tenerife. Captive, occurs in Australasia.

Joel Sartore / Photo Ark / Red-spectacled amazon (Amazona pretrei) portrait, Loro Park, Tenerife. Captive, occurs in South America.