Zoo Takes Seven Years To Realize That Their Hippo Was Not A Boy

 Somehow, a zoo in Japan had no idea that a hippo they thought a male was actually female. 

Japan's Osaka Tennoji Zoo took in a hippo named Gen-chan seven years ago and the paperwork said it was male.

They never checked until now.

The zoo says Gen-chan failed to make courtship calls to females and caretakers were never able to find boy parts.

They finally did a DNA test and discovered the truth. Officials say they won’t make this mistake again.