TOKYO, Japan (CNN) -- Puzzled zookeepers in northern Japan have discovered the reason why their attempts to mate two polar bears kept failing: Both are female.
The municipal zoo in the city of Kushiro in Hokkaido brought in a polar bear cub three years ago. They named it Tsuyoshi, after the popular baseball outfielder Tsuyoshi Shinjo, and waited until it reached reproductive age.
In June, the zoo introduced Tsuyoshi to its resident bear, an 11-year-old female named Kurumi, and waited for sparks to fly.
But much to the disappointment of zookeepers, Tsuyoshi never made any amorous advances toward Kurumi.
Earlier this month, zookeepers put Tsuyoshi under anesthesia to get to the bottom of the matter. That's when they made their discovery: Tsuyoshi is a female.
November 26, 2008
Zoo solves mystery of celibate polar bears
Perhaps I am confused, but I thought that the people running the zoos were supposed to know something about the animals. How do you miss this.