This undated image released by PBS shows an endangered Diademed sifaka (Propithecus diadema) at Lemuria Land in Madagascar. National Geographic photographer Joel Sartore is documenting thousands of rare animal species. His quest is detailed in the PBS series "Rare: Creatures of the Photo Ark," a three-part series debuting Tuesday at 9 p.m. EDT. (Joel Sartore/PBS via AP)
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