This animal deceived zookeepers for 7 years

Authorities have been deceived for seven years by a wild animal in Japan as they did not expect it to be the way it is.

A large hippopotamus that was thought to be a male for seven years turned out to be a female.

After the zookeeper noticed that the African native was not showing typical male behavior, they conducted a DNA test in which it was revealed that the 12-year-old was a female.

The hippo — named Gen-chan — came to Osaka in 2017 from Mexico. At that time, the documents showed termed it a male.

"We will keep doing our best to provide a comfortable environment to Gen-chan," Osaka Tennoji Zoo said.

The news was released last week on the zoo website in Japanese, about Gen-chan's sex.

According to the translated post, Gen-chan first arrived at their zoo from the African Safari animal park in Mexico when she was five years old, and was declared as a male.

It further added: “Because Gen-chan was still a calf at the time, they did not question the documents.”

As the mammal grew older, the zookeepers became suspicious about its behavior with no visibility of the male reproductive organ.

A spokeswoman for the Osaka Tennoji Zoo told AFP Tuesday that typical male hippo behaviour that Gen-chan was not displaying included making courtship calls to female hippos, or scattering faeces around while defecating with a propeller-like tail motion in order to mark territory.

The zoo's vice director Kiyoshi Yasufuku was quoted by the Mainichi newspaper: "We recognise the importance of confirming the sex, and we want to ensure that such mistakes will not happen again."