The Smithsonian Conservation Biology Institute both studies endangered animals and works to save them from extinction.
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Cheetah cub getting a check-up
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Adult cheetah
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Hippopotamus
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Ken Lang feeding endangered Prezwalski horse and calf
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Kandula the elephant calf
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Elephants
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Lion with cub
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Lioness with cub
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Pandas
Photography by Mehgan Murphy, Smithsonian's National Zoo