Japanese zoo mistook hippo's gender for 7 years

A Japanese zoo has announced a correction about the gender of their hippo after 7 years of confusion .

The Japan News reported that the rare incident occurred at the Osaka Tennoji Zoo in Osaka (Japan). Gen-chan, the 12-year-old hippo, is a 'resident' of the zoo and is identified as male.

Gen-chan the hippo. (Photo: Osaka Tennoji Zoo)

Osaka Tennoji Zoo received Gen-chan from a zoo in Mexico in 2017 when he was 5 years old. Mexican zoo staff said Gen-chan's gender is male and the necessary documents for entry clearly state that.

In August 2017, Osaka Tennoji Zoo decided to name the hippo Gen-chan after holding a naming contest. This name was chosen because it matches the energy of the male hippopotamus. Gen-chan became familiar to visitors to the zoo.

Hippos usually reach sexual maturity at around 10 years of age. However, zookeepers were disturbed because they did not see Gen-chan spreading feces to gain territory or court females, as males usually do.

Due to Gen-chan's large body, it was difficult to confirm with the naked eye the animal's gender through its reproductive organs, so the zoo requested DNA analysis in April. On April 16, Gen-chan was confirmed as a child.

Osaka Tennoji Zoo later announced: 'We have no doubts about Gen-chan's gender because it was identified as a male when sent from Mexico. Based on the results obtained, we recognize the importance of reconfirming the animal's gender and we are determined to ensure that this never happens again.'

Ultimately, Osaka Tennoji Zoo decided not to change Gen-chan's name.