The animals had been given to Maruyama zoo as a pair with the intention of leading them to breed

This article is more than 5 years old

This article is more than 5 years old

Zookeepers in Japan have abandoned a years-long attempt to have two spotted hyenas mate and reproduce as both turned out to be male.

The Maruyama zoo in Sapporo, northern Japan, said in a statement this week that it was given the animals as a “male and female couple” in October 2010 from a zoo in the South Korean city of Daejon.

“We have attempted to house them together for breeding many times but they often fought against each other and never engaged themselves in breeding behaviour,” the statement said.

Kami, the supposedly female hyena now five years old, showed no estrus symptoms after reaching sexual maturity, prompting the zoo to put it and its six-year-old partner Kamutori to sex tests.

“We have determined that the two animals are both male after conducting ultrasound imaging and hormone tests on them under anaesthesia,” the statement said.

The zoo explained that it is extremely difficult to determine the sex of a spotted hyena from the appearance of its external genitalia.

“We still plan to obtain a female spotted hyena for breeding with either Kami or Kamutori,” the statement said.