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NATIONAL GEOGRAPHIC EXPLORER
(ISSN 1541-3357) is published seven times during the school year—September, October, November–December, January–February, March, April, May—by National Geographic Society, 1145 17th Street NW, Washington, D.C. 20036. Postmaster: Please send address changes to Attn: Explorer Magazine, National Geographic Society, PO Box 291875, Kettering, OH 45429. Periodical postage paid at Washington, D.C., and additional mailing offices.
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EXPLORER, SEPTEMBER 2019 DIGITAL CREDITS: COVER: STEPHEN BELCHER/MINDEN PICTURES/AGE FOTOSTOCK. TOC: (BACKGROUND) RUDI_SUARDI/ISTOCK/GETTY IMAGES PLUS; (WARM UP, COOL DOWN) (FISH) EVGENIIA LITOVCHENKO/SHUTTERSTOCK; (TURTLE) RICH CAREY/SHUTTERSTOCK; (FLY & BUTTERFLY) ALE-KA/ISTOCK/GETTY IMAGES PLUS; (OCTOPUS) EVIKKA/SHUTTERSTOCK; (CHAMELEON) KUTTELVASEROVA STUCHELOVA/SHUTTERSTOCK; (RHINO) MARK CARWARDINE/PHOTOLIBRARY/GETTY IMAGES PLUS; (BIRDS) JUSTINE AMMENDOLIA/NATIONAL GEOGRAPHIC IMAGE COLLECTION. WARM UP, COOL DOWN: (FISH) EVGENIIA LITOVCHENKO/SHUTTERSTOCK; (TURTLE) RICH CAREY/SHUTTERSTOCK; (FLY & BUTTERFLY) ALE-KA/ISTOCK/GETTY IMAGES PLUS; (OCTOPUS) EVIKKA/SHUTTERSTOCK; (CHAMELEON) KUTTELVASEROVA STUCHELOVA/SHUTTERSTOCK; (LIZARD) © NICK HAWKINS/NATUREPL.COM; (LIZARD VIDEO) EYAL BAROV/PHOTOLIBRARY VIDEO/GETTY IMAGES; (LIZARD PHOTO) VISUALS UNLIMITED, INC/JOE MCDONALD/GETTY IMAGES; (SQUIRRELS) KEITH BOWSER/ALAMY STOCK PHOTO; (HAND & LIZARD) COURTESY OF NASA/JPL-CALTECH; (ELEPHANT & SPIDER) PHOTO RESEARCHERS/SCIENCE SOURCE/GETTY IMAGES PLUS; (CAT) TED KINSMAN/SCIENCE SOURCE/GETTY IMAGES; (WALKING VIDEO) PHOTOLIBRARY PTY LIMITED/OXFORD SCIENTIFIC VIDEO/GETTY IMAGES; (GHARIAL, MEERKATS & FLAMINGOS) COURTESY OF NASA/JPL-CALTECH; (DOG) PURPLE COLLAR PET PHOTOGRAPHY/MOMENT/GETTY IMAGES; (FENNEC FOX) MARCHIN DOBAS/ALAMY STOCK PHOTO; (KANGAROO) ANDREW WALMSLEY/ALAMY STOCK PHOTO; (IGUANA) © PETE OXFORD/MINDEN PICTURES; (WALRUS) © INGO ARNT/NATUREPL.COM; (MOUSE) ERIC ISSELEE/SHUTTERSTOCK; (SNAKE) KAMNUAN/SHUTTERSTOCK; (INFRARED MOUSE & SNAKE) EDWARD KINSMAN/SCIENCE SOURCE/GETTY IMAGES. HOT AND COLD: (BIRD) DRAKULIREN/SHUTTERSTOCK; (BUTTERFLY) BUTTERFLY HUNTER/SHUTTERSTOCK; (RHINO) GUALTIERO BOFFI/SHUTTERSTOCK; (FENNEC FOX) ROBERTS EASTMAN/ALAMY STOCK PHOTO; (FROG) © JEN GUYTON/NATUREPL.COM; (ALLIGATOR) RETILES4ALL/SHUTTERSTOCK. RHINO RESCUE: (BORDER) OKING/SHUTTERSTOCK; (BACKGROUND) MAXYM/SHUTTERSTOCK (RHINO EATING) MARK CARWARDINE/PHOTOLIBRARY/GETTY IMAGES; (RHINO LOOKING AT CAMERA) REYNOLD SUMAYKU/ALAMY STOCK PHOTO; (RHINO WITH KEEPER) © CYRIL RUOSO/MINDEN PICTURES; (HANDS & GLOBE) INCOMIBLE/SHUTTERSTOCK; (RHINO FACE) MARK CARWARDINE/PHOTOLIBRARY/GETTY IMAGES PLUS; (RHINO MOM & BABY EATING) MIKE SIMONS/GETTY IMAGES NEWS/GETTY IMAGES; (BINA) RSMULTIMEDIA/ALAMY STOCK PHOTO; (ANDALAS) GARY FRIEDMAN/LOS ANGELES TIME/GETTY IMAGES; (RATU & DELILAH) AFP/GETTY IMAGES; (ROSA) BAY ISMOYO/AFP/GETTY IMAGES; (ANDATU) COLBY BISHOP; (HARAPAN) XINHUA/ALAMY STOCK PHOTO; (ILLUSTRATIONS) JOHN TOMANIO/NATIONAL GEOGRAPHIC IMAGE COLLECTION; (MAP) JAMES LAUREN/NATIONAL GEOGRAPHIC IMAGE COLLECTION. THE PROBLEM OF PLASTICS: (BIRDS FLYING) JUSTINE AMMENDOLIA; (PLASTIC BITS) UKROLENOCHKA/SHUTTERSTOCK; (JUSTINE & BIRD) JOHANNA HOVINEN; (BIRD) JUSTINE AMMENDOLIA; (PLASTIC PILE) SASCHA CORTI/SHUTTERSTOCK; (JUSTINE PICKING UP TRASH) JESSICA MELVIN; (PLASTIC PLANT, HANDFUL OF PLASTIC & PERSON ON BEACH) JUSTINE AMMENDOLIA; (JUSTINE IN ARCTIC VIDEO) ADVENTURE CANADA; (MARINE TRACKER PHOTOS & VIDEO) JUSTINE AMMENDOLIA; (JUSTINE TAKING NOTES) FRANCE LIBOIRON; (MICROSCOPE PHOTOS) JUSTINE AMMENDOLIA; (JUSTINE VIDEO) JACKIE SATURNO; (JUSTINE WITH HARD HAT) TK. THE END: MARK CARWARDINE/ARDEA.COM/MARY EVANS PICTURE LIBRARY LTD/AGE FOTOSTOCK.