Photo: Win McNamee/Getty Images

Sukacita, a female Sumatran tiger cub, is dunked into a water moat by biologist Leigh Pitsko on Nov. 6 to test her swimming abilities at Smithsonian's National Zoo in Washington, D.C.

Born on Aug. 5, Sukacita and her brother, Bandar, must pass the swim test before they can join the rest of the tigers at the Great Cats exhibit. The cubs must be able to keep their heads above water, navigate the shallow end of the moat, and have the strength and agility to climb onto dry land on their own.

Sumatran tigers are critically endangered big cats native to the Indonesian island of Sumatra. Due to deforestation and illegal wildlife trade, it is estimated that only 400-500 individuals exist in the wild.

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Photo: Win McNamee/Getty Images

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Photo: Connor Mallon/Smithsonian's National Zoo

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Photo: Win McNamee/Getty Images

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Photo: Win McNamee/Getty Images

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Catie Leary is a photo editor at Mother Nature Network. Follow her on is a photo editor at Mother Nature Network. Follow her on Twitter and Google+

How do you teach a tiger how to swim?

Sumatran tiger cubs must pass a swimming test before joining the National Zoo's other tigers in the Great Cats exhibit.