DNA Discovery Solves Four-Year Mystery at Japan’s Maruyama Zoo

A case of mistaken identity at Maruyama Zoo in Sapporo, Japan, has brought international attention to the complexities of wildlife management after it was revealed that two spotted hyenas, once believed to be a breeding pair, were in fact both male. For four years, zookeepers had been puzzled as to why the animals, acquired in 2010, had not produced any cubs despite being paired together in a carefully managed environment. According to reports from the zoo’s management, staff initially assumed the absence of offspring was due to stress, behavioral issues, or adaptation difficulties common among animals living in captivity. However, after repeated failed breeding attempts, DNA testing was carried out, which confirmed that the supposed male and female hyenas were both male. Experts note that spotted hyenas are among the most difficult mammals to sex due to their unusual anatomy. Female hyenas possess external genitalia that closely resembles that of males, making visual examination unr...