Two Sumatran tiger cubs at the Smithsonian National Zoo pass their first swim test...

The three-month-old twin cubs paddled in front of their a mandatory aquatic exam before they are allowed to go on public display.

Craig Saffoe is the curator of Great Cats at the Zoo.

SOUNDBITE: Craig Saffoe, National Zoo's Curator of Great Cats, saying:

"I think these cubs did as well as any cubs could possibly have done. I think that if this was a pass/fail test, they would've passed with flying colors. They each went into the water, recognized almost immediately that they needed to turn themselves around and get to dry land, and they were both able to pull themselves out of the water on their own accord, and that's all we can ask."

A winning bidder in a charity auction paid 25 thousand dollars for the right to name the female cub - Sukacita - meaning "Joy" in Indonesian.

Zookeepers called her brother - Bandar - after a port in Sumatra.

The two cubs will go on exhibit in their yard starting November 18.

Sumatran tigers are considered critically endangered - and between only 400 and 500 currently exist in the wild.